It is generally believed that teaching is ________ it is a science .

[　　]

A．an art much as

B．much an art as

C．as an art much as

D．as much an art as

________ such heavy pollution already , it may now be too late to clean up the river.

[　　]

It is said that sight can be ________ by the use of proper glasses.

[　　]

With a lot of difficult problems ________ , the newly-elected president is having a hard time.

[　　]

—Is it my age ________ the boss minds?

—I am afraid not. He will consider ________ necessary to have an experienced assistant.

[　　]

We hope that such measures to control prices ________ are taken by the government will work .

[　　]

He's perfectly ________ to live in the mountain and paint pictures all day.

[　　]

—How do you find the football match?

—Wonderful, I think. Just as fine as ________ of the matches we have ever seen.

[　　]

—Were you busy last weekend?

—Very . Rather than ________ time playing cards as usual , I devote every effort to ________ an advertisement.

[　　]

A．wasting; making

D．waste; make

C．to waste; make

D．a waste of ; making

By the time he ________ at the station, it ________ dark .

[　　]

A．arrived; got

B．had arrived; had got

C．had arrived; got

D．arrived; was getting