求助！！

小昱

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.

这道题为什么选D啊？？ 忘各位大侠指点下~

小昱

全句划线。。

ptlove4ever

这应该是蓝色OG上面的原题吧？
这题全句都划线，因此难度更大。建议楼主见到这种题目就三步走：读原文、比选项、改错误
第一，    读原文。句子主干：it had not been announced. 其中的it= the first pulsar。意即：星星没有被宣布。星星怎么能被宣布呢？应该是the discovery of pulsar（对星星的发现）被宣布，故排除。
第二，    比选项。先排除肯定错误的选项，再对比A与剩余选项的区别，但本题一上来就可以排除A选项所以只需要剩余选项互相比较
1、B：独立主格逻辑主语与主语不一致。Although not announced…的主语应该是the discovery，对星星的发现没有被宣布，而主句的主语却是graduate student。因此排除。
2、C：独立主格逻辑主语与主句主语不一致。Although observed…的主语应该是the first pulsar，是星星被看见，但主句主语却是the discovery。因此排除。
3、E：主谓不一致。主语：The pulsar，谓语：was not announced。星星怎么能被宣布呢？应该是the discovery of pulsar才能被宣布。因此排除。
此时，已经只剩下D选项了。我们不妨看看它为什么对。
D：句子主干：The first pulsar was observed but the discovery was not announced.
星星被观测到，但这项发现未被宣布。主谓一致，时态正确，因此就是最正确的选项。
综上，全句最重要的是抓住：独立主格逻辑主语与主语应该一致以及主谓一致。pulsar能被observed，the discovery能被announced。
见到这样全部划线的题目，千万不要在心里给自己暗示：哎呀，好难，肯定做错或者看不懂。只要耐心按三步走的方法来一一剖析，一定就能找出正确的答案。

小昱

灰常感谢