单选题A gate valve installed in a pipeline should be （）.Aused in either the fully dosed or fully opened positionBinstalled with the stem downCused for steam service onlyDused to throttle or regulate the flow of liquid
单选题
A gate valve installed in a pipeline should be （）.
A
used in either the fully dosed or fully opened position
B
installed with the stem down
C
used for steam service only
D
used to throttle or regulate the flow of liquid
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