71. The passage mentioned which of the following with respect to the fragments of comet Shoemaker-Levy-9?
(A) They were once combined in a large body.
(B) Some of them burned up before entering the atmosphere of Jupiter.
(C) Some of them are still orbiting Jupiter.
(D) They have an unusual orbit.

1994年7月，發生了一系列令人震驚的事...