在阀门出口用压力表检查消防水泵停泵时,水锤消除设施后的压力不应超过水泵出口设计额定压力的()。
A.1.2倍
B.1.4倍
C.1.6倍
D.2.0倍
参考答案:B
The manager ______ the workers how to improve the program since 9 am.
A.has told
B.is telling
C.has been telling
D.will have told
下列属于组织培养的是:()
A.花粉离体培养成单倍体植株
B.芽发育成枝条
C.根尖分生区发育成成熟区
D.未受精的卵发育成植株