大全512，高手请教

1.        More than five thousand years ago, Chinese scholars accurately described the flow of blood as a continuous circle controlled by the heart, but it went unnoticed in the West.

(A) but it went

(B) but it was

(C) although it was

(D) but the discovery went（D）

(E) although the discovery was

请问为什么选D，如何排除其他的，

go unnoticed  is a fixed idiom

本题主要考点：

1. it 指代不清，在指代一整个主语时，只能用名词或which指代这个现象，OG里有一道很经典的，大家翻翻

2. 英文里though, although都表示"虽然"，but表示"但是"；这种情况特别容易误导我们在英文句子里犯错误：因为though, although引导主从复合句，表示"虽然……但是"，有让步的含义； but引导并列句也表示"虽然……但是"，表转折。本句在语法和逻辑上，the discovery指代Chinese scholars accurately described the flow of blood as a continuous circle controlled by the heart。所以在这里无论是语法角度还是逻辑角度，都应该选择but

3. be和go的区别，go在这里描述一个变化，这里应该维持句子原意！且go unnoticed为idiom.

大侠出手，就是不一样啊！多谢指点，我想通了