502. Many writers of modern English have acquired careless habits that damage the clarity of their prose, but these habits can be broken if they are willing to take the necessary trouble.

(A) but these habits can be broken

(B) but these habits are breakable

(C) but they can break these habits

(D) which can be broken（C）

(E) except that can be broken

我选了A。我看有的解释说如果选A,读者会以为后面那个they指these habits。

可是下划线前已经有个"their prose"了,和后面的"they"呼应应该不会出现歧义了吧,明显一起指代 writers，为什么还选C呢?我觉得两个they摆一起挺拗口。

but开始一个新的分句，分句的代词不受前面句子的制约，所以产生歧义是必然的，A没有C好。

遗漏了情态动词can

并且动词优于形容词