The man was punished ____? what he had done．
A．a(chǎn)s B．since C．because D．because of
此題應(yīng)選D.容易誤選C,因?yàn)榘戳?xí)慣思維：because之后接從句,而because of之后接名詞或代詞.
其實(shí),because作為從屬連詞,用以引導(dǎo)原因狀語(yǔ)從句,其后應(yīng)是一個(gè)不含有引導(dǎo)詞的句子,而不能是what引導(dǎo)的從句.另一方面,本題中的what he had done＝the thing（s）that he had done.也就是說(shuō),這個(gè)what-從句從本質(zhì)上看它相當(dāng)于一個(gè)名詞,所以要選because of.
請(qǐng)看以下類似的例子：
She cried because of what you said．她哭是因?yàn)槟阏f(shuō)的話.
He left angrily because of what you said at the meeting．他生氣地離去,是因?yàn)槟阍跁?huì)上說(shuō)的話.
He was sentenced to death because of what he had stolen from the bank．他被判處死刑,是因?yàn)樗麖你y行所偷的東西.
注意：若用because,則其后的從句不應(yīng)有引導(dǎo)詞：
Mr Smith couldn't come because he was ill．史密斯先生因病不能來(lái).（比較：He couldn't come because of his illness．）
The sports meet was put off because the weather was bad．
運(yùn)動(dòng)會(huì)因天氣不好而推遲.