Which of the following is effective topic sentence?
A.This paragraph will deal with the college library.
B.I am going to write about my job as a gas station attendant.
C.I do push-ups and sit-ups each morning.
D.Computers are changing our society.
E.Exercising every morning has had psitive effects on my health.
F.Using computers to teach school Children is a mistake.
正确答案：Exercising every morning has had psitive effects on my health.；Using computers to teach school Children is a mistake.