大全section4—17

pianer

Although just inside the orbit of Jupiter, amateur astronomers with good telescopes should be able to see the comet within the next few weeks.
(A) Although just inside the orbit of
(B) Although it is just inside the orbit of
(C) Just inside the orbit of
(D) Orbiting just inside
(E) Having orbited just inside
选B这里的主语不是amateur astronomers 吗？那么前面的it is有指什么？我选的是D.但是D得意思貌似和原句不一样，所以错，是这样吗？

pianer

 谢谢。这下懂了！！！

evenlasting

it是单数，指代后面的comet，astronomers是复数，可以区分开来不会歧义。
选D的话，分词的逻辑主语和主句的主语一致，变成了astronomers orbit inside ... ，这样就产生逻辑错误了。