In those days John with his classmates kept busy preparing for the exam.A. isB. areC. wa

问题补充：

In those days John with his classmates kept busy preparing for the exam.

A. is

B. are

C. was

D. were

答案：

A. is

B. are

(答案→)C. was

D. were

解析：本题中在那些天表示的是过去，用过去时，本题的主语中心词是John，为单数第三人称，故用was，故本题选C。