The rocket engine, with its steady roar like that of a waterfall or a thunderstorm, is an impressive symbol of the new space age. Rocket engines have proved powerful ________(1) to shoot astronauts ________(2) the earth’s gravitational ________(3) and put them on the moon. We have now ________(4) space travelers.
Impressive and complex ________(5) it may appear, the rocket, which was ________(6) in China over 800 years ________(7), is a relatively simple device. Fuel that is ________(8) in the rocket engine changes ________(9) gas. The hot and rapidly expanding ________(10) must escape, but it can do so only ________(11) an opening that heads ________(12). As the gas is ________(13) with great force, it ________(14) the rocket in the ________(15) direction. Like the ________(16) of a gun when it is fired, it ________(17) the ________(18) of nature described by Sir Isaac Newton when he found that “________(19) every action, there is another equal and opposite ________(20).”
1.[单选题]___- A.travelers
- B.astronauts
- C.researchers
- D.explorers
3.[单选题]___- A.same
- B.other
- C.opposite
- D.wrong
4.[单选题]___- A.that
- B.so
- C.as
- D.sometimes
6.[单选题]___- A.shown
- B.been
- C.appeared
- D.proved
7.[单选题]___- A.described
- B.discussed
- C.considered
- D.made
8.[单选题]___- A.in advance
- B.before
- C.earlier
- D.ago
9.[单选题]___- A.turns
- B.goes
- C.faces
- D.directs
10.[单选题]___- A.that
- B.when
- C.although
- D.if
11.[单选题]___- A.transmitted
- B.dispersed
- C.erected
- D.radiated
12.[单选题]___- A.send
- B.land
- C.take
- D.carry
13.[单选题]___- A.states
- B.proves
- C.follows
- D.breaks
14.[单选题]___- A.heating
- B.escaping
- C.expanding
- D.conducting
15.[单选题]___- A.against
- B.despite
- C.beyond
- D.from
18.[单选题]___- A.attracts
- B.leads
- C.pulls
- D.pushes
19.[单选题]___- A.made
- B.discovered
- C.developed
- D.invented
20.[单选题]___- A.round
- B.contained
- C.stored
- D.burned
参考答案: A,D,C,C,B,D,A,D,C,C,D,B,C,C,C,D,B,D,D,D