－Isn't it a surprise that I happened to meet Francis Mathews at the Christmas Party last week?

－If my memory serves me correctly, you ________ each other for exactly two years．

hadn't seen

haven't seen

didn't see

don't see

When it ________ air pollution, Beijing faces the three“C”s－cars, coal and construction, which lead to Beijing's thick air pollution．

refers to

comes to

happens to

speaks to

________ it have been the failure to pick up directions from the ground control that caused the air crash?

Must

Could

Would

Should

The one concern for parents and students is ________ the student pursues their university education in a foreign country, the student will not have the opportunity to establish social contacts in China．

that

that if

whether

how

After the quarrel, I tried all my best to fix the misunderstanding between us, but all my efforts seemed ________．

in trouble

in case

in effect

in vain

Failure hurts grown-ups and children________, but it can make a positive contribution to your life once you learn to use it．

actively

likely

alike

similarly

If the food tastes nice, I'll go to buy some more; ________, I won't go．

if not

when not

if any

when ever

The silence of the library is sometimes broken by a sudden cough or the sound of pages ________．

turning

turned

being turned

having turned

Not until the train pulled into the next station ________ her suitcase gone．

Mary had found

had Mary found?

did Mary find

Mary found

________ no cash for food, he broke into an old woman's house, hoping to steal some money．

Because

As

Since

With