OG9

145.   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  ETS explains that "since the pronon one is sufficient to introduce the modifier and the sentence is more flued without that" BY  chapter 2 says"同位语从句是有one that……“

那究竟要不要省略that 呢？

同例

1.        The proposed urban development zones do not represent a new principle; it was employed in “Operation Bootstrap” in Puerto Rico.

(A) do not represent a new principle; it

(B) represent not a new principle, but one that

(C) are not a new principle; the same one

(D) are not a new principle, but one that（B）

(E) are not new in principle; it

B

1.        The science of economics, which for four decades was dominated by Keynesians, who at first stressed the government’s role in stimulating the economy, but who were ultimately led away from solutions based on government intervention.

(A) economics, which for four decades was

(B) economics that was to be

(C) economics, one which has, for four decades, been

(D) economics is one that for four decades has been（D）

(E) economics, for four decades, is one that was

d

雪落，

og9 that 是关系代词代宾语，可省略

后面两题that代主语，不可省略

Thank you  for your  explanation.

that如果引导宾语从句, 一定不能省略.

that如果引导定语从句: 1. 如果that在从句里做主语, 不能省略; 2. that在从句里做宾语, 省略.

但上面的2在OG里有反例. 243就是that做后面的宾语而不省略的. 这并不是ETS自相矛盾, 而是补出that避免歧义. 所以, 没有绝对的规律, 只有相对的正确, 因为语言的魅力在于灵活.

在这里HIGHLIGHT部分有点不理解，在这一题中怎么判断THAT作主语还是宾语？