I failed in the final examination last term, and only then ________ the importance of study．

A．I realized

B．I had realized

C．had I realized

D．did I realize

Seeing the ________ flood, she was ________ to take the boat．

A．scaring scaring

B．scared scared

C．scaring, scared

D．scared scaring

Joe had changed so much that I could hardly ________ him at first in Shanghai Expo Garden．

A．remember

B．realize

C．ignore

D．recognize

It's the second time that I ________ in Beijing．What great changes! It's years since I ________ here last time．

A．have been; left

B．had been; left

C．went; had left

D．have; had left

He was about to go out to search for Lily ________ the girl called him．

A．while

B．as

C．when

D．before

The reason ________ he was late is ________ his bike was broken．

A．why because

B．that that

C．because that

D．why that

The factory ________ we'll visit next week is not far from here．

A．which

B．where

C．in which

D．to which

The thief ran away before I was ________ of what had happened．My wallet was stolen

A．aware

B．accused

C．tired

D．ashamed

________ meeting held last night was ________ great success．

A．A, \

B．A, the

C．The, a

D．The, the

What is the way the professor thought of ________ the puzzle to get the truth?

A．to work out

B．working out

C．having worked out

D．being worked out