Polluted air and water kill plants， animals， and even people．（ ）
| A． |
can |
B． |
can't |
C． |
should |
D． |
shouldn't |
Miss Li，could you please help me____this math problem？
OK．Let me try．（ ）
A．look upB．work outC．set up
Must I wait here all morning？I have a lot of work to do．
No，you____．You may be back in the afternoon．（ ）
A．mustn'tB．can't
C．don't have to
Grandma is rather deaf，so you must speak clearly and___to her．（ ）
A．quietlyB．loudlyC．noisily
I'd like to hold our next meeting____June 23rd．Is that OK for you？（ ）
A．inB．atC．on
s Tom____boy in your class？
Yes．Nobody is taller than him．（ ）
A．the tallestB．the strongest
C．the cleverest