_________ my dear teacher couldn't understand was _________ fewer and fewer middle school students showed interest in her lessons．

A．What; why

B．That; what

C．What; because

D．Why; that

The most important thing about cotton in history is _________ part that it played in _________ Industrial Revolution．

A．/,/

B．the,/

C．the, the

D．a ,the

It doesn’t matter how much loss we have suffered; just avoid _________ the mistake again．

A．to make

B．being made

C．having made

D．making

Just as sound travels through the air in waves, electricity travels through the air in _________ radio waves．

A．what is called

B．which is called

C．what it is called

D．which it is called

It was _________ of Jack to turn off the radio when I was sleeping in the bedroom．

A．considerable

B．considerate

C．disturbing

D．sensible

A student will be immediately dismissed if he/ she is found _________ in school．

A．smoke

B．smoking

C．to smoke

D．smoked

I failed again in the exam and only then _________ how much time I had wasted．

A．I realized

B．did I realize

C．I had realized

D．had I realized

If you think there _________ huge quantities of oil for the use of drivers, you are wrong．

A．is

B．are

C．has

D．have

The chairman thought _________ necessary to invite Professor Smith to speak at the meeting．

A．that

B．it

C．this

D．him

There are the books _________ my brother．

A．belonged to

B．belonging to

C．that are belonged to

D．belong to