How to teach speaking skill to 11 graders in a communicative way effectively a case study at nguyen trai high school m a 60 14 10

VIETNAM NATIONAL UNIVERSITY – HOCHIMINH CITY UNIVERSITY OF SOCIAL SCIENCES AND HUMANITIES HOW TO TEACH SPEAKING SKILL TO 11 GRADERS IS A COMMUNICATIVE WAY EFFECTIVELY A CASE STUDY AT NGUYEN TRAI HIGH SCHOOL Submitted in partial fulfillment of the requirements for the degree of Master of Art (tesol) Submitted by VÕ THỊ THY Supervisor ĐẶNG THỊ HƯỞNG, Ed.D Ho Chi Minh City, December 2009 STATEMENT OF AUTHORSHIP I certify that this thesis entitled “HOW TO TEACH SPEAKING SKILL TO 11th GRADERS IN A COMMUNICATIVE WAY: A CASE STUDY AT NGUYEN TRAI HIGH SCHOOL” is my own work This thesis has not been submitted for the award of any degree or diploma in any other institutions Tay Ninh, 31st December, 2009 Vo Thi Thy RETENTION AND USE OF THE THESIS I hereby state that, Vo Thi Thy, being candidate for the degree of Master of TESOL, accept the requirements of the University relating to the retention and use of Master’s Thesis deposited in the Library In terms of these conditions, I agree that the original of my thesis deposited in the Library should be accessible for purposes of study and research, in accordance with the normal conditions established by the Library for care, loan, and reproduction of theses Ho Chi Minh City, 31st December, 2009 Vo Thi Thy ACKOWLEDGEMENTS First, I would like to express my deep gratitude to my thesis supervisor, Dr Dang Thi Huong, who has given me valuable assistance over the long period of carrying out the research and writing this thesis She has devoted her time to reading all the chapters of my draft versions carefully, provided me with invaluable comments, criticism and the best advice on how to gradually improve my work Without her constant guidance, I could not have completed it Second, I would like to send my geat gratefulness to all the teaching staff of the Department of English Linguistics and Literature, University of Social Sciences and Humanities, National University in Ho Chi Minh City for their devotion to the success of the M.A program Third, I am greatly indebted to the Vietnamese teachers of English and students at Nguyen Trai High School, Trang Bang District, Tay Ninh Province who all have enthusiastically helped me accomplish this thesis Last but not least, I send my special thanks to my mother and my parents-in-law, my husband, my sisters and brothers, teachers, and my friends who have constantly given me favour, sympathy and encouragement They have made a great contribution to the completion of my thesis ABSTRACT The focus of my thesis is to work out underlying principles in creating “communicative need” for modifying communicative speaking activities in Tieng Anh 11 textbook as well as ways of teaching English speaking skill in a communicative way effectively This is a case study at Nguyen Trai High School, Trang Bang District, Tay Ninh Province Survey questionnaires for both teachers and students were designed The questionnaire for teachers was delivered to Vietnamese teachers of English at NTHS to investigate their current ways of teaching English speaking skill It aims at finding out how much teachers can make use of the designed speaking activities in the textbook in a communicative way The questionnaire for students was delivered to the two groups, controlled and experimental, to probe their different perceptions of and reactions to the two ways of teaching speaking skill during the experimental time In the experiment, 90 students were divided into two groups of equal ability They were trained for 16 weeks in the second semester of the school year 20082009 In the controlled group, students were instructed to practise ready-designed speaking activities in the new textbook In the experimental group, students were asked to conduct newly-modified speaking tasks in which communicative need was created and a number of principles for making an activity communicative and tips for a communicative speaking class were applied At the end of the experimental time, a speaking test was carried out to test each student’s speaking skill of the two groups of student subjects to see whether the experimental group was more successful in communication than the other group The findings showed that students in the experimental groups had more positive attitudes toward speaking classes during the experimental time than the other More students in the second group were successful in making themselves understood than the first one They talked more and used the target language in a more fluent and natural way than the other The results proved that the principles suggested were actually effective in making a speaking activity communicative itself, which is a prerequisite for the success of a speaking class Besides the principles, a number of techniques for teaching the skill communicatively were also proposed In the last chapter, some conclusions and recommendations for the teachers and the administrators of the school were also made TABLE OF CONTENTS Page Statement of authorship i Retention and use of the thesis ii Acknowledgement s iii Abstract iv Tables of content vi List of tables ix List of figures x List of diagrams xi Abbreviations xii CHAPTER I: INTRODUCTION 1.1 Background to the study 1.2 The aims of the study 1.3 Significance of the research .5 1.4 The overview of the research .5 CHAPTER II: LITERATURE REVIEW 2.1 The differences between written and spoken language .7 2.2 Speaking in real life and speaking in classroom 2.2.1 The nature of real-life communication 2.2.2 The distinction between speaking in real life and speaking in classroom 12 2.3 Language competence and performance 18 2.3.1 Communicative competence 20 2.3.2 Oral communicative activities 24 2.4 Testing speaking 27 2.4.1 Criteria for a speaking test 27 2.4.2 Reliability and validity of a speaking test 28 2.4.3 Types of speaking test 31 2.4.4 How to test speaking ability 32 2.5 Using textbooks 34 CHAPTER III: METHODOLOGY 3.1 Research questions 37 3.2 Research design 37 3.2.1 Characteristics of subjects 38 3.2.2 Instruments 40 3.2.2.1 The questionnaires 41 3.2.2.2 Testing speaking 43 3.2.3 Data collection procedure 44 CHAPTER IV: DATA ANALYSIS AND DISCUSSIONS 4.1 Teachers’ responses to the questionnaires .46 4.1.1 Teachers’ attitudes toward teaching English speaking skill 46 4.1.2 Teachers’ awareness of the existence of communicative need in speaking activities 47 4.1.3 Teachers’ intention of creating communicative need for speaking activities .47 4.1.4 Teachers’ frequency of using oral communicative activities 48 4.1.5 Teachers’ other techniques in using communicative activities 49 4.1.6 Teachers’ difficulties in teaching English speaking skill 50 4.1.7 Conclusions .52 4.2 Students’ responses to the questionnaire and scores of the speaking test 52 4.2.1 Students’ responses to the questionnaire 53 C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 4.2.1.1 Students’ attidutes toward learning English speaking skill 53 4.2.1.2 Students’ perceptions of and reactions to speaking classes 54 4.2.1.3 Group B’s perceptions of and reactions to games used .54 4.2.1.4 Group B’s perceptions of and reactions to roleplays used 56 4.2.1.5 Students’ perceptions of and reactions to communicative situations 58 4.2.1.6 Students’ perceptions of and reactions to how they the tasks… ………………………………….61 4.2.1.7 Learners’ success in making themselves understood 63 4.2.1.8 Students’ average talking time in speaking classes 64 4.2.1.9 Learners’ difficulties in speaking classes 65 4.2.2 Students’ scores of the speaking test 67 4.2.2.1 Fluency 68 4.2.2.2 Task completion 69 4.2.3 Conclusion 70 CHAPTER V: CONCLUSIONS AND RECOMMENDATIONS 5.1 Conclusions 71 5.2 Recommendations 73 BIBLIOGRAPHY 75 APPENDICES 79 Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an LIST OF TABLES Table 3.1: Information on teachers’ age and gender 38 Table 3.2: Information on teachers’ background 39 Table 3.3: Students’ background information 40 Table 4.1: Teachers’ attitudes toward teaching English speaking skill 46 Table 4.2: Teachers’ awareness of the existence of communicative need in speaking activities 47 Table 4.3: Teacher’s frequency of modifying speaking activities 48 Table 4.4 : Teachers’ intention of creating communicative need 48 Table 4.5: Teachers’ frequency of using oral communicative activities in teaching English speaking skill 49 Table 4.6: Teachers’ other techniques in using communicative activities 49 Table 4.7: Teachers’ difficulties in teaching speaking skill 50 Table 4.8: Students’ attitudes toward learning English speaking skill 53 Table 4.9: Students’ difficulties in learning English speaking skill 65 Table 4.10: Students’ average scores at English in the first semester, school-year 2008-2009 68 Table 4.11: Fluency scores 68 Table 4.12: Task completion scores 69 Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 105 APPENDIX LESSON PLAN Unit SPEAKING (Guessing game) Objectives By the end of the period, SS will be able to talk about special occasions in Vietnam and around the world Method/ Techniques Communicative approach Model-practice Guessing Teaching aids Handouts with information gap Procedure Teacher’s and SS’ activities Content I.Pre-speaking Task 1: Gap-filling (attached) T provides input for S by having them gap-filling tasks in groups Different groups work on different special days and keep them secret from each other II.While-speaking Example questions The groups work in a competition: One volunteer of each group stands in front of class and has their group’s secret information about the special day Who celebrates this special day? What people on this special day? When they celebrate it? ……………………………… The other groups take turns to ask questions to find out what special day it is The group who can guess right will win the game III.Post-speaking What did you last Mid-Autumn Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 106 T asks orally and some individuals answer festival, Valentine’s Day, Teacher’s Day? IV.Homework: More practice outside class V Drawing experience Gap-filling Birthday Who celebrate? Ex: Vietnamese people, American people, Japanese people, etc… or people around the world? Why people celebrate? Ex: The people celebrate the day when someone was _ _ _ _ What people do? Ex: They hold a p _ _ _ _, have birthday c_ _ _, blow ca_ _ _ _ and make w_ _ _ es for the new age When people celebrate? Ex: ………………… Vietnamese Teacher’s Day Who celebrate? Ex: Vietnamese people, American people, Japanese people, etc… or people around the world? Why people celebrate? Ex: The people celebrate it to s _ _ w their gratefulness (lòng biết ơn) to their ……… What people do? Ex: Teachers hold a p _ _ _ _ in the sc_ _ _ _, students give their teachers p_ _ _ _ _ _s (=gift) and fl_ _ _ _s or c_ _ _s Students also w_ _ _ best things to their teachers When people celebrate? Ex: ………………… Valentine’s Day Who celebrate? Ex: Vietnamese people, American people, Japanese people, etc… or people around the world? Why people celebrate? Ex: The people celebrate it to express their _ _ _ _ to each other Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 107 What people do? Ex: They give c_ _co_ _ _ _s, fl_ _ _ _s and p_ _ s_ _ _s to the people they love When people celebrate? Ex: ………………… Christmas Who celebrate? Ex: Vietnamese people, American people, Japanese people, etc… or people around the world? Why people celebrate? Ex: The people celebrate the day when Jezus Christ was _ _ _ _ What people do? Ex: They hold a p_ _ _ _ for all family members and relatives, go to c_ _ _ _ _, s _ _ _ and listen to songs like Jingle Bells, etc When people celebrate? Ex: ………………… Thanksgiving Who celebrate? Ex: Vietnamese people, American people, Japanese people, etc… or people around the world? Why people celebrate? Ex: People celebrate the h_ _ve_t What people do? Ex: Family members g_ t together They prepare a large meal with roast t_ _key When people celebrate? Ex: ………………… Mid-Autumn Festival Who celebrate? Ex: Vietnamese people, American people, Japanese people, etc… or people around the world? Why people celebrate? Ex: People celebrate the largest full _ _ _ _ in the year What people do? Ex: Ch _ _dren enjoy this day most They play with lante_ _ and candles People eat _ _ _ _cakes and drink _ _ _ When people celebrate? Ex: ………………… Women’s Day Who celebrate? Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 108 Ex: Vietnamese people, American people, Japanese people, etc… or people around the world? Why people celebrate? Ex: People express their love to their M_ _ _ers, female t_ _c_ _ _s and girlfriends What people do? Ex: Men or boys celebrate parties for women and girls they love They give them f_ _ _ _ _s, g_ _ _s to show their love When people celebrate? Ex: ………………… Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 109 APPENDIX LESSON PLAN Unit 14 SPEAKING (Discussion and Problem-solving task) Objectives By the end of the lesson, SS will be able to Find a solution to a problem given Use some functions of English: agreeing and disagreeing, giving opinions Techniques Communicative approach Groupwork and discussion Teaching aid: Workcards Procedure Teacher’s and SS’ activities Content I.Pre speaking Task 1: The following are some phrases that can be used to express agreement and disagreement Put (A) beside an expression of SS it quickly, then compare agreement, (D) beside an expression of the answers with their partner disagreement and (G) beside an expression of giving opinion T gives the answers phrase by Useful language phrase on powperpoint ……….In my opinion, …………… ……….As far as I’m concerned………… T gives some small practice: ……….Great! For example: ……….That’s a good idea I think we should go to Cu Chi ……….Let’s that tunnel for picnic this weekend ……….I think ……………………… Do you agree? ……….I personally think that ………… I think we should bring rice ……….I quite agree with you papers ………I don’t think that’s a good idea …………………… ………I can’t agree with you more …………………………… …… That’s a good idea, but ………… SS work in a group of or SS take down the ideas to fill in the form Task 2: Imagine you have a day-off this week Make a plan for your group’s picnic Decide on Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 110 T walks around to give instant help SS from each group put questions for other groups to get information about the picnics T gives feedback following Destination:……………………………… Means of transport: ……………………… What to bring: Foods: ……………………………… Drinks: ……………………………… Others: …………………………… Initerary: When to start? ……………………………………… What to in the morning? …………………………….? What to in the afternoon …………………………… What to in the evening ………………………… When to finish? …………………………… III.Post speaking: Task 3: Exchange the reports among groups IV.Homework More practice outside class V.Drawing experience Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 111 APPENDIX ANOVA FIGURES ON STUDENTS’ SCORES OF THE SPEAKING TEST Theoretically, in order to prove whether there is a difference in a factor between two groups, Anova tool in Excel sofeware is used In particular, the P value is compared with 0,05 If it is smaller than 0,05, we come to the conclusion that there is a clear difference Following is the result on students’ scores of fluency and task completion: Fluency: A comparison between the experimental and controlled groups Anova: Single Factor SUMMARY Groups Count Sum Average Variance 11A4 11A6 45 45 640 405 14.22222 5.631313 12.04545 ANOVA Source of Variation SS df MS F Between Groups Within Groups 613.6111 777.7778 88 613.6111 8.838384 69.42571 1391.389 89 Total P-value 9.69E13 F crit 3.949321 Table 1:Anova figure on fluency of the two groups The figures in Table indicates that P value is much smaller than 0,05 (P= 9,96E-13= 9,96.10 -13 < 0,05) This proves that there is a clear difference in fluency scores: more students in group B can speak English more fluently than those in group A Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 112 The figures in Table shows that P = 2,27E-08= 2,27 10 -8