The number of people invited to the conference 150 but a number of them absent for diffe

问题补充：

The number of people invited to the conference 150,but a number of them absent for different reasons.

A. were;was

B. were;were

C. was;were

D. was;was

答案：

A. were;was

B. were;were

(答案→)C. was;were

D. was;was

解析：the number of+名词复数作主语时，谓语动词用单数；a number of+名词复数作主语时，表示“许多/大量的……”，谓语动词用复数。