合作学习理论认为，在班级教学中，学生群体的组织形式有三种，即( )。

多项选择题形成性评价与总结性评价的( )不同。

多项选择题听、说、读、写的训练内容与形式应尽可能______。

单项选择题William Sidney Porter, known as O. Henry, is most famous for ().

A. his poems
B. his plays
C. his short stories
D. his novels

单项选择题The girl must have been reading at this moment last Sunday,（）she

A.wasn’t
B.didn’t
C.mustn’t
D.hadn’t

单项选择题Tim is in good shape physically () he doesn't get much exercise.

A. if
B. even though
C. unless
D. as long as