-Harry up!There are only ten minutes________.
A.leave B.to leave C.left D.leaving
参考答案是C,为什么??
The machine needs_______once a year in order to work properly
A.to check B.checking C.check D.checked
参考答案是B,为什么??为什么不选A
We were very sad and angry to hear that the bad milk powder_______the deaths of over 30 babies.
A.made B.put C.caused D.gave
参考答案是C,为什么???为什么不选A???
Would you please_______the street when the traffic light is red?
A.not cross B.don't cross C.not to cross D.aren't crossing
参考答案是B,为什么??为什么不选C????
各位帮帮忙,这是暑假的预习作业啊···