Although the first pulsar, or rapidly spinning collapsed star, to be sighted was in the summer of 1967 by graduate student Jocelyn Bell, it had not been announced until February, 1968.

(A) Although the first pulsar, or rapidly spinning collapsed star, to be sighted was in the summer of 1967 by graduate student Jocelyn Bell, it had not been announced until February, 1968.

(B) Although not announced until February, 1968, in the summer of 1967 graduate student Jocelyn Bell observed the first pulsar, or rapidly spinning collapsed star, to be sighted.

(C) Although observed by graduate student Jocelyn Bell in the summer of 1967, the discovery of the first sighted pulsar, or rapidly spinning collapsed star, had not been announced before February, 1968.

(D) The first pulsar, or rapidly spinning collapsed star, to be sighted was observed in the summer of 1967 by graduate student Jocelyn Bell, but the discovery was not announced until February, 1968.

(E) The first sighted pulsar, or rapidly spinning collapsed star, was not announced until February, 1968, while it was observed in the summer of 1967 by graduate student Jocelyn Bell.

答案是d。

感觉这题只能用排除法。

但是d选项我有一点想不通，to be sighted  在这里是什么意思。 按照sight的意思来说，它根observe是重复的。

我用这里理由，排除了d的

是的。

不过我的一个缺点就是，用一个理由排除掉几个选项后，就不会再看它们，然后对剩下的2个选项就采用非常宽松的标准。尤其是长句子，是我的超级弱项。唉

to be sighted 应该是修饰the first pulsar. or rapidly spinning collapsed star 只是插入语。

was observed 是首句的谓语。

不知道我的理解对不对啊，欢迎批判~

The first pulsar to be sighted 不定式限定修饰，因此才有 the, 如果缺少

这个不定式修饰就只能用 a first pulsar, or rapidly spinning collapsed star,

was observed in the summer of 1967 by graduate student Jocelyn Bell, but

the discovery was not announced until February, 1968.

Although the first pulsar, or rapidly spinning collapsed star, to be sighted was in the summer of 1967 by graduate student Jocelyn Bell, it had not been announced until February, 1968.

(A) Although the first pulsar, or rapidly spinning collapsed star, to be sighted was in the summer of 1967 by graduate student Jocelyn Bell, it had not been announced until February, 1968.

(B) Although not announced until February, 1968, in the summer of 1967 graduate student Jocelyn Bell observed the first pulsar, or rapidly spinning collapsed star, to be sighted.

(C) Although observed by graduate student Jocelyn Bell in the summer of 1967, the discovery of the first sighted pulsar, or rapidly spinning collapsed star, had not been announced before February, 1968.

(D) The first pulsar, or rapidly spinning collapsed star, to be sighted was observed in the summer of 1967 by graduate student Jocelyn Bell, but the discovery was not announced until February, 1968.

(E) The first sighted pulsar, or rapidly spinning collapsed star, was not announced until February, 1968, while it was observed in the summer of 1967 by graduate student Jocelyn Bell.

A中，the pulsar was in the summer of 1967逻辑不正确

B中 announced 的逻辑主语应该是the discovery但是实际主语为graduate student

C中,observed逻辑主语应该为pulsar但是实际主语为the discovery

D没有明显错误....

E中，pulsar was announced逻辑不正确