___________do people greet visitors？ Some shake hands． Some say "hello" or "hi"．Some kiss．（ ）
A．WhyB．WhatC．How
The talent show is ______ the game show．I like both．（ ）
A．as boring asB．not so bored as
C．as interesting asD．not so interested as
Our country is taking action to ______ air pollution．（ ）
A．cut downB．cut upC．cut outD．cut off
The girl in the classroom ______ be Sarah．She has gone to the library．（ ）
A．mayB．mustC．can'tD．needn't
We have worked so long．Shall we stop ______ a rest？（ ）
A．haveB．to havingC．havingD．to have
Rules are helpful to us，______ we have to follow them．（ ）
A．soB．butC．orD．because