做好完形填空要掌握足够的词汇量，在做的时候还要掌握理解上下文的意思。下面的完形填空，大家用来练习把！
Directions: In this section, there are 10 blanks in the following. For each blank there are four choices marked A, B, C and D. You should choose the right answer that best fits into the passage.
Perhaps more than anything else, scientists are eager to find out if Martian life existed in the past-or still exists. 61 telescopes first zoomed in 62 Mars in the 17th century, people have conjured up a wild 63 of images or what Martians might look like. But space probes like the 1997 Sojourner land rover have yielded no evidence of such alien beings.
Most experts agree that if life did at one time evolve on Mars, finding evidence of that life which would likely take the tiny organisms won’t be easy. 64 , many scientists are optimistic. “We’ve got organisms on Earth that adapted to life deep 65 the surface in underground water wells,” says Stephen Clifford. “ 66 life like that evolved on Mars four billion years ago, there’s no reason why it 67 today.”
68 lat year’s disappointing losses, the future of Martian exploration looks 69 . This year, two major films about fictitious Mars missions ----Red Planet and Missions to Mars----are certain to heighten interest in our planetary neighbor. More important, plants for new sets of NASA orbiters and landers ---- one to launch in 2001, the other in 2003---- are already in the works. Without a doubt, each new mission will inch scientists closer to 70 the mysteries of planet Mars.
61. A. When B. Before C. Ever since D. Ever
62. A. in B. on C. in the D. on the
63. A. varying B. various C. plenty D. variety
64. A. Still B. Even if C. Though D. Although
65. A. up B. under C. below D. above
66. A. When B. What C. That D. If
67. A. wouldn’t exist B. wouldn’t have existed C. doesn’t exist D. has existed
68. A. Even if B. Despite C. Although D. However
69. A. promised B. being promised C. promising D. to be promised
70. A. understand B. understanding C. be understood D. the understanding
答案：61-65 CBDAC 66-70 DABCB
