单项选择题
Litmus paste is used in order to determine（）.
A.innage B.thievage C.ullage D.the tank's datum point
单项选择题 Joiner bulkheads on a vessel provide（）.
单项选择题 Individual wires，used in systems greater than 50 volts,（）.
单项选择题 Increasing the number of slack liquid tanks has the effect of raising the（）.
