承力索的张力差不得大于额定张力的()%。
A.±5
B.±10
C.±15
D.±20
参考答案:B
There _____________ some milk in the bottle. [ ]
A. are
B. is
C. has
D. have
属于高危险物品和器材是()
A.纤支镜
B.胃镜
C.喉镜
D.活检钳
E.压舌板