单项选择题
Individual wires，used in systems greater than 50 volts,（）.
A.should be supported at 24 inch intervals with plastic tie wraps B.should never be located in a tank C.must be installed in conduit D.All of the above
单项选择题 Increasing the number of slack liquid tanks has the effect of raising the（）.
单项选择题 In which case is the IOPP Certificate of an inspected vessel NOT invalidated? （）
单项选择题 In setting the valves on a steam-smothering system on a tanker，the master control valve to cargo tanks should be（）.
