－How was the televised debate last night?

－Super!Rarely ________ so much media attention．

A．a debate attracted

B．did a debate attract

C．a debate did attract

D．attracted a debate

With the help of high technology, more and more new substances ________ in the past years．

A．discovered

B．have discovered

C．had been discovered

D．have been discovered

－Guess what!I have got A for my term paper．

－Great!You ________ read widely and put a lot of work into it．

A．must

B．should

C．must have

D．should have

－Did you tidy your room?

－No, I was going to tidy my room but I ________ visitors．

A．had

B．have

C．have had

D．will have

Alan is a careful driver, but he drives ________ of my friends．

A．more carefully

B．the most carefully

C．less carefully

D．the least carefully

The mayor has offered a reward of $ 5000 to ________ who can capture the tiger alive or dead．

A．both

B．others

C．anyone

D．another

Leaves are found on all kinds of trees, but they differ greatly ________ size and shape．

A．on

B．from

C．by

D．in

Today, we’ll discuss a number of cases ________ beginners of English fail to use the language properly．

A．which

B．as

C．why

D．where

I ________ there little more than a week when I set to work with the scientist．

A．would be

B．have been

C．had been

D．will be

－________ when has the country been open to international trade?

－1978, I suppose．

A．Since

B．In

C．From

D．After