Allen always behaves_____， so many people like him．（ ）
A．easilyB．politelyC．friendlyD．lively
___________do people greet visitors？ Some shake hands． Some say "hello" or "hi"．Some kiss．（ ）
A．WhyB．WhatC．How
We will cause less pollution _____________we can find ways to reuse or recycle more rubbish．（ ）
A．unlessB．ifC．though
Most of us enjoy __________to our mothers speak， because our brains greatly prefer the voices of our own mothers．（ ）
A．listeningB．listenC．to listen
Kelly White loves all sports， __________skating．（ ）
A．graduallyB．seriouslyC．especially
Only plants and animals that need very little water __________live in a desert．（ ）
A．canB．needC．must