John ___ such a thing about you. He never speaks ill of you behind your back.

Scientists say it may be five years _____ it is possible to test this medicine on human patients.[ ]

Help yourself to some more meat，Linda. —____．

We have ______ Art lesson ______ every Monday.

A nature reserve for white-flag dolphins was set up in 1992, _______ boats have beenprohibited from sailing around since then