9、Techniques to employ the energy of the sun are being developed.
A) convert
B) store
C) use
D) receive
标准答案： c
10、Since the Great Depression， the United States government has protected farmers from damaging drops in grain prices.
A) slight
B) surprising
C) sudden
D) harmful
标准答案： d
11、Cement was seldom used in building the Middle Ages.
A) crudely
B) rarely
C) originally
D)occasionally
标准答案： b
12、Medicine depends on other fields for basic information， particularly some of their specialized branches.
A) conventionally
B) obviously
C) especially
D) inevitably
标准答案： c
13、We were astonished to hear that their football team had won the champion.
A) amazed
B) amounted
C) amused
D) approached
标准答案： a
14、There is an abundant supply of cheap labor in this country.
A) a steady
B) a plentiful
C) an extra
D) a stable
标准答案： b
15、The most crucial problem any economic system faces is how to use its scarce resources.
A)puzzling
B) difficult
C) terrifying
D) urgent
标准答案： d