We ______ for quite a long time.a、were keeping waitedb、were kept waitedc、were keeping waitingd、were kept waiting

We ______ for quite a long time.
a、were keeping waited
b、were kept waited
c、were keeping waiting
d、were kept waiting

D 被要求等 keep doing sth

c、were keeping waiting
keep doing sth
或者be kept to do sth
所以选C

d

d be kept doing