单项选择题
A.fell off B.fell away C.fell out D.fell through
A. It is already outdated. B. Many of the penguins have died for lack of food. C. Their wearing of flipper bands has affected the accuracy of the data.
A.Teenagers usually take notes in the dark during lectures. B. It’s convenient for teenagers to carry around at night. C. Teenagers with eye problems can’t see the keyboard clearly.