空车安全阀弹簧自由高低于()或折断时更换。
A.40mm
B.50mm
C.60mm
D.70mm
参考答案:D
15. --- Who are the teenagers gathering at the school gate?
--- Well, if you _____ know, they are all my visiting students.
A.need
B.must
C.may
D.Will
药物流产的禁忌证是
A.哺乳期妊娠者
B.生殖道畸形者
C.孕7周内的妇女
D.剖宫产不足半年者
E.已诊断或可疑异位妊娠者