请教各位

dnwei

Astronomers at the Palomar Observatory have discovered a distant supernova explosion, one that they believe is a type previously unknown to science.

(A)  that they believe is

(B)  that they believe it to be

(C)  they believe that it is of

(D)  they believe that is

(E)   they believe to be of

[此贴子已经被作者于2008-10-27 21:45:44编辑过]

connie4895

(E)?