[問題]PP-test1 Q26 Structure

[winkat]

小弟在作文法題目的時候，發現下列這題的標準答案是B，可是我覺得D比較對耶!能請高手回答一下我錯在哪裡嗎?謝謝!!

26. _________ directly with most metals to form compounds called carbides.
A. Carbon reacting
B. Carbon reacts
C. The reaction of carbon
D. When carbon reacts

[Jessy]

http://www.formosamba.com/phpBB3/viewtopic.php?t=2041

請註明出處,謝謝

[micki]

頂.

[HHC]

如果你選D，那主要子句在哪裡呢？
(when引導的是副詞子句)