keep silence和keep silent

Both are correct!
However, I would use keep silent! It's because most people use "keep silent". To avoid mark being deducted, use keep silent!
If you really want to use keep silence, please do you use it directly.
e.g. Thw woman kept a respectful silence.
Use keep + adj + silence

2009-04-07 13:49:25 補充：
Sorry, it should be
f you really want to use keep silence, please DON'T you use it directly.

2009-04-07 13:50:18 補充：
Not "Thw" but "The".
Sorry for my typing mistakes.

兩者皆對!

不過 「Keep silent」 比較常用。

Silent 是 形容詞 --- 安靜的 、無聲的

例: Miss Chan tells Tom to keep silent. (陳老師叫Tom保持安靜)

安靜在這句是形容「Tom」, 所以用形容詞 silent是對的。

Keep silence 也沒有錯,

silence 是 名詞 -- keep silence 也解保持安靜,

文法、語法也沒錯。

２個都對，keep silent在英語社會說話上比較普遍, 但信不信由你,這個問題是很多外國大學裏都有討論過的問題. 基本上,2個都不是錯.

silence 可以係動詞, 可以係名詞; 而silent係形容詞。所以keep silence應用名詞才是正確:保持安靜。

Keep Silent is the correct form.

Silent is an adj., and in a sentence, where noun is omitted, there should be a verb and a adj. It would not be right if it is a verb followed by another noun.