×
单选题
两个活门上的旋转螺母都与内部阀杆上的螺纹啮合，从而使阀杆松开或拉紧到金属阀座。
A
The swivel nuts on both valves engage threads on an internal stem that loosens or draws tight the valve stem to a metal seat.
B
The rotating nuts on both valves are meshed with the threads on the inner valve stud, so that the valve stud is loosened or tightened to a metal valve base.
C
The swing nuts on both valves engage with the threads on the internal spool, allowing the spool to loosen or tighten to the metal seat.
答案解析
正确答案：A
相关知识点：
活门螺母阀杆考点速记
相关题目
单选题
Examine the tubing for worn areas.
单选题
The sealant burns at 109 deg. F.
单选题
Apply the paint with a brush.
单选题
Move the panel into position.
单选题
Attach the two ends of the hose.
单选题
Install the larger bolts.
单选题
Replace components that are worn more than the maximum limits.
单选题
Correct the tension.
单选题
Make sure that the movement of the elevators is slow.
单选题
Assemble the unit.
