语法(Page 167)

B

1.The ponderosa pine is _____ of most of the timber used by forest product firms in the Black Hills of South Dakota.

(A)the source

(B)as source

(C)the source which

(D)because the source

2.Computers that once took up entire rooms are now _____ to put on desktops and into wristwatches.

(A)small enough

(B)smaller than

(C)so small

(D)as small as

3.According to some educator,the goal of teaching is to help students learn what _____ to know to live a well-adjusted and successful life.

(A)do they need

(B)they need

(C)they are needed

(D)as they may need.

4.The sapphire's transparency to ultraviolet and infrared radiation makes _____ in optical instruments.

(A)it is of use

(B)it uses

(C)it a useful

(D)it useful

5._____ initial recognition while still quite young.

(A)Most famous scientists achieved.

(B)That most famous scientists achieved

(C)Most famous scientists who achieved

(D)For most famous scientists to achieve.

6.Mango trees,_____ densely covered with glossy leaves and bear small fragrant flowers,grow rapidly and can attain heights of up to 90feet.

(A)whose

(B)which are

(C)are when

(D)which

7._____,the Canadian composer Barbara Pentland wrote four symphonies,three concertos,and an opera,among other works.

(A)An artist who,prolific

(B)Is a prolific artist

(C)Prolific an artist

(D)A prolific artist.