... future tense. (Unit 14) 9. Defining and Non-defining relative clauses. (Unit 15) 10. Although as a contrasting connector. (Unit 15) B. exercises Unit 9 and 10 I. Phonetics 1. A. beef B. beer ... conservation? Conservation is the safeguarding and presevation of natural resources 2. Will the world’s resources never be used up? Yes, they will. 3. What is concerned with the prevention ... fight against pollution of our environment, in particular, the dirtying and poisoning of air and water. Conservation is also concerned with the reclaiming of land by irrigating desert, draining swamps...