IELTS writing task 1 while sentences

IELTS Writing Task 1: 'while' sentences In writing task 1, you usually need to make comparisons A good way to this is to write a complex sentence using the word 'while' I wrote two such sentences in my essay last week Look carefully at where I put the comma in each sentence 1) 'while' at the beginning of the sentence: While the numbers of people who use the car and train increase gradually, the number of bus users falls steadily 2) 'while' in the middle of the sentence: In 1970, around million UK commuters travelled by car on a daily basis, while the bus and train were used by about million and million people respectively