You will fall behind others ________ you work hard．

A．if

B．unless

C．though

D．since

We find ________ impossible for us to learn a foreign language well in a short time．

A．that

B．this

C．one

D．it

－________ will you finish doing the work?

－In a few weeks．

A．How long

B．How far

C．How soon

D．How often

China has ________ area of about 9, 600, 000 square kilometers．

A．a

B．an

C．the

D．/

She got up to get some sleeping pills but found there was ________ left at home．

A．nothing

B．none

C．something

D．nobody

Man's understanding of nature is developing ________．It never stays at the same level．

A．at the right time

B．for the first time

C．from time to time

D．all the time

The old theatre will close soon ________ some extra donations are made．

A．so

B．if

C．because

D．unless

My father doesn't like shopping much．He would rather ________ TV at home than

________ around for hours in shops．

A．watch; walk

B．watch; to walk

C．to watch; to walk

D．to watch; walk

The lady in this photo ________ be over fifty! She looks so young!

A．mustn't

B．must

C．can't

D．can

If the robot ________ wrong, you can get a new one for free or get all your money back．

A．went

B．goes

C．would go

D．will go