og9 对句式结构的困惑

dearjane

OG9。么时候省略that。

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）

(E) they believe to be of

e 这个答案没问题，one they believe to be 是同位语从句么？one 是 believe 的宾语么？还是 one 后面接的是省that 的定语从句？

谢谢指点

zxding

首先  个人觉得必须要用的  of a type结构   of必须要有  否则句子意思就不对了

这样   在C/E之间选E就比较好理解了

dearjane

我明白这个题的答案，可就是想搞懂这个画线部分的结构。谢谢