问题补充：
The number of people invited fifty, but a number of them absent 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：
这题考查的是主谓一致，第一空填was因为主语是the number of“…的数量”谓语用单数，第二空填were，因为主语是a number of“许多”谓语用复数。选C。
