OG124 support for?

During Roosevelt’s years in office Black Americans began voting for Democrats rather than Republicans in national elections, but Black support for Democrats at the state and local levels developed only after when civil rights legislation was supported by Harry Truman.

(A) developed only after when civil rights legislation was supported by Harry Truman

(B) developed only after when Harry Truman supported civil rights legislation

(C) developed only after Harry Truman’s support of civil rights legislation

(D) develops only at the time after the supporting of civil rights legislation by Harry Truman（C）

(E) developed only after there being Harry Truman’s support of civil rights legislation

这个support for 我不懂.  看了以前紫草NN的解释说是名词,固定用法. 可如果是这样,怎么能和and developed 并列呢?? 名词短语和句子并列? 说不通啊?

想了老久了,也想不通. 帮帮我吧.  非常感谢

During Roosevelt’s years in office Black Americans began voting for Democrats rather than Republicans in national elections, but Black support for Democrats（主语） at the state and local levels（介词短语） developed（谓语） only after Harry Truman’s support of civil rights legislation。（时间状语）

black在这里是名词。Black support for Democrats 的意思是黑人对于民主党的支持。

正确答案里没有and developed 呀？何谈平行呢？

Black support for Democrats 是与 Harry Truman’s support of civil rights legislation平行的。而且平行的很好。

Black is a ADJ.?    hehe

LOL!!!

Black => adj. = Black American's. For example: March is Black History Month in US.