单项选择题
A.gums, acids, and varnishes B.removed by cellulose type filters C.neutralized by oil additives D.not removed by absorbent filters
If an anchor windlass has been idle for some time, you ...
单项选择题If an anchor windlass has been idle for some time, you should （）.
A.repack all valve stems B.lubricate it prior to use C.replace the foundation bolts D.balance the warping heads
The color of the flame on a halide torch without any re...
单项选择题The color of the flame on a halide torch without any refrigerant present is （）.
A.blue B.green C.orange D.purple
