________ to nuclear radiation, even for a short time, may produce variants(变体)of genes on human bodies．

Being exposed

Having exposed

Exposed

After being exposed

Finding information in today’s world is easy．The ________ is how you can tell if the information you get is useful or not．

ability

competition

knowledge

challenge

Mr．Green stood up in defence of the 16-year-old boy, saying that he was not the one ________．

blamed

blaming

to be blamed

to blame

His mother opened the drawer to ________ the knives and spoons．

put away

put up

put forward

put together

He was too trusting－or to ________ it another way, he had no head for business．

infer

talk

put

respect

It is said that more than one student ________ that film so far．

is to see

have seen

has seen

is seeing

________, the excited crowds in the square suddenly became so quiet．It’s still puzzling．

Personally

Naturally

Somehow

Anyway

Our bad living habits will destroy the earth．Only by changing ________ we live can we save the earth．

that

what

how

where

It’s hard to imagine an Olympic opening ceremony ________ fireworks exploding in the night sky．

without

while

where

with

When ________ to danger and conflict, men tend to increase blood pressure, ________ nervous and anxious．

exposed; felt

exposed; feeling

exposing; feeling

exposing; felt