对夹紧装置的操作要求是:方便、安全、(),有利于快速装卸工件。
A.准确
B.省力
C.变形小
D.可靠
参考答案:B
When she first arrived in China,she wondered what the future might have ________ for her,but now all her worries are gone.
A.in need
B.in time
C.in preparation
D.in store
某药物在有对照组的研究中,在妊娠3个月的妇女未见到对胎儿危害的迹象,可能对胎儿影响甚微,按照药物妊娠毒性分级,属于()
A.A级
B.B级
C.C级
D.D级
E.X级