泵房内的止回阀宜采用带有______的旋启式止回阀和其他密封性能好,具有缓闭功能、消声功能的止回阀。
A.引入管 B.调压阀 C.水表 D.旁通管
参考答案:D
____ after a long walk, Henry called me and said he couldn’t come to the meeting.
A.Having worn out
B.Being worn out
C.To wear out
D.Worn out
商品的品质包括商品的内在素质和( )
A.内在品质
B.物理性能
C.化学成分
D.外观形态