37.At present, a probable inducement for countries to initiate large-scale space ventures is .

　　A) international cooperation C) scientific research

　　B) nationalistic reasons D) long-term profits

　　38. What is the main goal of sending human missions to Mars?

　　A) To find out if life ever existed there.

　　B) To see if humans could survive there.

　　C) To prove the feasibility of large-scale space ventures.

　　D) To show the leading role of science in space exploration.

　　39. By saying “With Mars the scientific stakes are arguably higher than they have ever been” (Line 1, Para, 4), the author means that .

　　A) with Mars the risks involved are much greater than any previous space ventures

　　B) in the case of Mars, the rewards of scientific exploration can be very high

　　C) in the case of Mars, much more research funds are needed than ever before

　　D) with Mars, scientists argue, the fundamental interests of science are at issue

　　40. The passage tells us that proof of life on Mars would .

　　A) make clear the complex chemistry in the development of life

　　B) confirm the suggestion that bacterial fossils travelled to Earth on a meteorite

　　C) reveal the kind of conditions under which life originates

　　D) provide an explanation why life is common in the universe

　　參考答案：

　　Unit 5

　　21.D 22.A 23.B 24.C 25.D 26.D 27.A 28.C 29.B 30.A

　　31.A 32.D 33.C 34.A 35.B 36.D 37.C 38.A 39.B 40.C