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 1 powerful enough to shoot astronauts 2 the earth's gravitational pull and 3 them on the moon. We have now become 4 space.
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 10 gas must escape, but it can do so only 11 an opening that 12 backward. As the gas is 13 with great force, it 14 the rocket in the 15 direction. Like the kick of a gun 16 it is fired, it 17 the laws of nature 18 by Sir Isaac Newton when he discovered that“19 every action, there is 20 equal and opposite reaction.”
n ared ed
nst ite nd
y
elers onauts archers orers
times
overed loped nted
advance re ier
d ained ed ed
ing ping nding ucting
ugh
s s cts
smitted ersed ted ated
acts s s es
r site g
ough
es es ows ks
ribed ussed idered
her
1.【答案】D
【解析】因其後接形容詞powerful作表語故應填系詞。shown不是系詞;been和appeared雖可作系詞但與句意不符;而proved可作系詞，意為“證明是”，符合句意。
2.【答案】C
【解析】根據意思判斷，beyond意為“超出，超過”。
3.【答案】B
【解析】因land on意為“使……著陸”,而send, take和carry表示“把……送到……上去”時,常接介詞to,故應選land.
4.【答案】A
【解析】根據意思判斷，travelers正確.
5.【答案】C
【解析】原句是表示讓步的狀語從句，而且是一個