The class big. Now the class practicing swimming.A. are ;areB. is ;isC. is ; areD. are ;

问题补充：

The class big. Now the class practicing swimming.

A. are ;are

B. is ;is

C. is ; are

D. are ; is

答案：

A. are ;are

(答案→)B. is ;is

C. is ; are

D. are ; is

解析：考查主谓一致：句中第一个class指的是班级这个整体，属于单数名词，故用is；第二个class指的是班上的同学，为复数，故用are。