土方施工机械一般分为()两大类。
A、开挖、运输
B、回填、压实
C、开挖、压实
D、运输、回填
参考答案:C
Teachers have to constantly update their knowledge in order to maintain their professional________.[ ]
A. consequence
B. independence
C. competence
D. intelligence
延胡索对中枢神经系统影响的描述,不正确的是()
A.镇痛作用与脑内阿片受体无关
B.延胡索乙素镇痛作用最强
C.具有镇静、催眠作用
D.对钝痛的作用优于锐痛
E.具有呼吸抑制、便秘等副作用