To do it a bit for the motherland, ________．

working hard is necessary

to work hard is necessary

one should work hard

it is necessary to work hard

Only when ________ got enough information ________ come to a sound conclusion．

have you; can you

you have; you can

you have; can you

have you; you can

These animals are all used to their environment, ________, they have learned how to live successfully in their habitat．

however

for instance

what's more

or rather

We couldn't catch up with the others because they ________ too long before us．

were starting

have started

had started

started

It was not just the size of the party last night ________ made it unique, but ________ it meant to our country．

which; that

that; what

that; because

that; that

I can't find my key．It ________ in my office．

can be forgotten

can be left

must have been forgotten

must have been left

An unhappy childhood may have some negative effects on a person's character; however, they are not always ________．

practical

avoidable

permanent

beneficial

________ help the people in the snowstorm in the south made him worried．

Not known how to

Unknown what to do to

His knowing not how to

His not knowing how to

Criticized as online games are, they never fail to ________ a large number of teenagers．

appeal to

object to

refer to

turn to

The Internet gives people the ________ to have the information they look forward ________ to them quickly and cheaply．

chance; to deliver

change; deliver

access; to delivering

chance; to delivered