重症抑郁症是指症状持续（）
A.3天以上
B.1周以上
C.2周以上
D.4周以上
E.3个月以上
参考答案：C
—Hi, Lin Tao. I didn't see you at the party.
—Oh, I _______ ready for the maths exam. [ ]
A. got
B. was getting
C. have got
D. am getting
SQ21型切丝机切丝刀的有效工作长度为（）mm左右。
A、72
B、82
C、90
D、92
