成人高考考试

【单选题】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 (76) powerful enough to shoot astronauts (77) the earth’s gravitational pull and (78) them on the moon. We have now become (79) in space.
Impressive and complex (80) it may appear, the rocket, which was (81) inChina over 800 years (82) , is a relatively simple device. Fuel that is (83) in the rocket engine changes (84) gas. The hot and rapidly (85) gas must escape, but it can do so only through an opening that faces backwarD、As the gas is radiated with great force, it pushes the rocket in the opposite direction.
A．in advance
B．before
C．earlier
D．ago

网考网参考答案：D
网考网解析：
[考点] 时态题 [解析] ago“在……以前”。该句为which引导的定语从句，意为“中国发明火箭是在距今800多年前”。句中谓语是一般过去时，故应选D。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>