题目内容：

Oumuamua,an object through space that was discovered on October 19th, has already made history.The speed at which it is moving relative to the sun means that it cannot be native to the solar system. Its official name is thus II/2017 UI, with the “I” standing for “interstellar(星际)”—the first time this name has ever been used.

That is exciting.Some scientists, though, entertain an even more exciting possibility: what if Oumuamua is not an asteroid(小行星),as most think, but an alien(外星的)spacecraft? Asteroids come in ll sorts of shapes and sizes, but Oumuamua seems particularly different.As best as astronomers can tell, it is cigarlike,being roughly 180 meters long but only about 30 meters wide.That makes it longer than anything known of in the solar system.Such a shape would be a sensible choice for a spaceship,since it would minimize the scouring(冲刷)effect of interstellar dust.

With that in mind the Breakthrough Listen project, an organization aimed at hunting for alien life, plans to turn the world’s biggest radio telescope,the Green Bank instrument in Virginia,towards Oumuamua to see if it can hear anything interesting.Oumuamua is currently about twice as far from Earth as Earth is from the sun. At that range,the telescope should be sensitive enough to pick up a transmitter about as powerful as a mobile phone after just a few seconds—worthy of observations.

Will it find anything? Almost certainly not.Oumuamua has the same reddish color as many as asteroids,so probably has a similar composition.And, if it really is a spaceship, it is strange that signs of its artificial origin have not been seen already.It could, in theory, be a derelict(遗弃星球). But in that case the telescope is unlikely to hear anything. By far the most likely option is that it is exactly what it seems to be: a huge space rock, one that has come to the solar system from the vast space between the stars.

1.What makes some scientists think Oumuamua is possibly an alien spacecraft?

A. Its size.    B. Its color.

C. Its shape.    D. Its speed.

2.What does the underlined word“that”in the third paragraph probably mean?

A. The research into the solar system.

B. The purpose of hunting for alien life.

C. The effect of interstellar dust on Oumuamua.

D. The possibility of Oumuamua being a spaceship.

3.What is Oumuamua most likely to be according to the author?

A. An asteroid.    B. A space rock.

C. Interstellar dust.    D. An alien spacecraft.

4.It can be inferred from the last paragraph that__________.

A. Oumuamua will return to where it’s from soon

B. Oumuamua’s real identity remains to be found out

C. astronomers have not seen signs of Oumuamua’s artificial origin

D. the Green Bank telescope has already heard something from Oumuamua