-- Are you a teacher -- I______, but now I am working in a company.
A. is
B. am
C. was
D. had
If only we ______ then, the disease was curable.
A. knew
B. could know
C. had known
D. would have known
4,你和同事合作领导演讲稿,集体会议时有人指出有一部分是抄袭的,你发现是你同事负责的部分,你怎么办
She ought to stop working; she has a headache because she ______ too long.
A. has been reading
B. had read
C. is reading
D. read