It is said that ____ young people may lose the abilities to hear after five years if they listen to MP4 players which are too loud for more than five hours a week.

Elephants have their own way to tell the shape of an object and ________ it is rough or smooth.

Do you enjoy My heart will go on?—No, I prefer songs loud.

Helen has two sisters and a brother. Her brother is working, but _________her sisters are still at school.

The principal is not here, and you’d better call him ______ 3 p.m. ______ 5 p.m. tomorrow. [ ]