三道选择题
I have never seen her _
A. to smile B. to smiling C smiling D。 smile 这道题为什么选D
there is nothing for us to do except _ the meeting.
A .to put off B.put off C.putting off D.to be put off answer:B why?
charles babbage is generally considered _ the first computer.
A.to have invented B.inventing C.to invent D.having invented answer: A why?