TOEFL Reading: ETS-TOEFL阅读机经 - JTH8036K1SY731V8L$

Paragraph 2 supports the idea that comets appear very small when they first become visible from Earth because A. the glow from the nucleus hides the rest of the comet from view B. they are still too far away from the Sun to have developed a coma or a tail C. their various gases have mostly become vaporized D. they are relatively small when compared to the visible planets