题目内容：

Efficient ways of studying do good to students,______ it's necessary for them to find them.
A and however B thus C therefore D and thus

优质解答

前后有因果关系的意思,后面要表达so...之类,从上意思来看可以选BCD,但是thus用在分句了中,一般是表达“从而”如“Agriculture has developed rapidly,thus providing light industry with ample raw materials.农业...