The number of the teacher invited twelve but a number of them late for different reason

问题补充：

The number of the teacher invited twelve, but a number of them late for different reasons.

A. were; was

B. was; was

C. was; were

D. were; were

答案：

A. were; was

B. was; was

(答案→)C. was; were

D. were; were

解析：考查主谓一致。The number of…指“…的数量”；做主语的时候，谓语动词使用单数形式；a number of…指“许多…”修饰可数名词复数形式，在句中做主语时，谓语动词使用复数形式。句意：被邀请的老师的数量是12，但是很多老师都因为各种原因迟到了。故C正确。