单项选择题
The medicine （） cool, clean and dry.
A.must keep B.must be kept C.must be keep D.must be in
单项选择题 “Must we start the experiment now?” “No, you （）.”
单项选择题 He keeps（）at himself in the mirror.
单项选择题 Don't disturb me. I（）letters all morning and have written ten so far.
