___ the employees' working efficiency, the supervisor will allow them to have a coffee break.

A salty diet may increase the risk of stomach cancer ________ 10 percent, South Korean researchers found in a study of more than 2 million people．

Some students often listen to music _____ classes to refresh themselves.

I’m badly in need ______ your help.

It was considerate _____ you not to play the piano while I was asleep.