___________do people greet visitors? Some shake hands. Some say "hello" or "hi". Some kiss.
A.Why B.What C.How
We will cause less pollution _____________we can find ways to reuse or recycle more rubbish.
A.unless B.if C.though
Most of us enjoy __________ to our mothers speak, because our brains greatly prefer the voices of our own mothers.
A.listening B.listen C.to listen
Kelly White loves all sports, __________skating.
A.gradually B.seriously C.especially
Only plants and animals that need very little water __________ live in a desert.
A.can B.need C.must
It's hard to turn down a banana. They taste good and you don't have to wash them__________eating them.
A.until B.after C.before
