题目内容：
Read the following two sentences and decide the way the second sentence uses to revise the first sentence?When they were confronted with problems in study or life, some students behave bravely, while other students act timidly. Confronted with problems in study or life, some students behaved heroically, others selfishly
A.It revises the unnecessary passive construction.
B.It revises the unnecessary expletive construction.
C.It revises the focus of the sentence.
D.It reduces clauses to phrases, and phrases to words.
参考答案：