There is a big gap ________ the teenagers and the adults．

A．among

B．between

C．in

D．of

Air pollution can affect humans by ________ sore eyes and respiratory problems, especially in children and ________．

A．cause; the old

B．causing; the older

C．causing; the elderly

D．cause; the elderly

Because of ________, the environment ________ worse and worse．

A．pollution; have got

B．pollution; is getting

C．keeping; gets

D．to keep; getting

Let sunlight in while ________ much of the warmth from ________ out．

A．keeping; getting

B．to kept; getting

C．keep; ti get

D．to keep; getting

There was a strange sound outside．Mary went out and ________ around, but she ________ nothing．

A．saw; saw

B．looked; saw

C．watched; looked

D．looked; watched

Is there anything ________ to you?

A．that is belonged

B．that belongs

C．that belong

D．which belongs

I was listening to the music ________ there was a knock at the door．

A．while

B．when

C．because

D．until

Study hard, ________ you're sure to have a good result in the exam!

A．hut

B．and

C．for

D．or

He swims faster than ________ boy in his class．

A．any

B．the other

C．all the other

D．any other

The ________ of machine made us feel sick．

A．voice

B．noise

C．sound

D．noises