It is hard to imagine what I ________ today if I hadn't been admitted to Nankai Middle School 15 years ago.

would have done

will do

am doing

would be doing

Not until they left school ________ how much their teachers loved them and helped them．

they realized

did they realize

they had realized

had they realized

________ three times in a row, the boxer decided to make a fourth attempt, though．

Having defeated

To have defeated

Having been defeated

To defeat

________ is well known is that Africa had contacts with India and the Red Sea civilizations from the earliest times．

As

It

What

That

The truly homeless are the rich who ________ their home into a hotel hall．

will turn

turned

are turning

have turned

All the drivers have been warned that driving after drinking shall ________ serious accidents．

bring up

bring back

bring in

bring about

Depression is the leading cause of suicide, ________ in turn is the third leading cause of death among 15 to 24 year olds in the United States．

who

which

that

what

Everyone agrees that the Philippine police ________ for the tragedy that Hong Kong tourists were killed．

are to blame

are to be blamed

are being blamed

have blamed

In ________ year 751, the Chinese traveler Du Huan was taken ________ prisoner by the Arabic army．

a, the

/, the

the, a

the,/

All the characteristics distinguishing birds ________ other animals can be traced to prehistoric times．

to

between

for

from