—Have you ever visited the Opera House?
—Yes．When I was in Sydney, I__ _it twice．
| A．had visited | B．visited | C．have visited | D．would visit |
The doctor tried his best to save this patient.At last he began ___.
| A．to come | B．to come to life | C．to come up | D．to come up to |
He was sitting in an armchair, ___ a novel
| A．reading | B．read | C．was reading | D．to be reading |
Only then ___ that he had made a mistake.
| A．he realized | B．did he realized | C．realized he did | D．did he realize |
--Do you like to study mathematics?---____? I like it very much.
| A．No | B．Not | C．Why not | D．Not why |
The students of Class Two said that they had no difficulty ___ those sentences into English.
| A．to put | B．of putting | C．for being put | D．in putting |