每台水泵的出水管上应设( )，并应采取防水锤措施 A.
阀门 B.
止回阀 C.
压力表 D.
流量计

单项选择题Primary prevention refers to health promotion, _______________________________________, as well as specific protection against the inception of disease. （ ）A.which promotes wellness in general and thus reduces the likelihood of disease, disability and premature death in a specific mannerB.which enhances wellness in general and thus reduces the likely of disease, disability and premature death in a nonspecific mannerC.which fosters wellness in general and thus reduces the likelihood of disease, disability and premature death in a nonspecific mannerD.which fosters wellness in general and thus reducing the likelihood of disease, disable and premature death in a nonspecific manner

多项选择题6.2.1 剖切平面主要选择：