空调水系统中的空调水管的压力管一般可选用（）。
A．不锈耐酸钢无缝钢管
B．镀锌钢管
C．铸铁管
D．混凝土管
参考答案：B, C
转子流量计的转子位子越高，流量越大。
In a married falls rig at the after end of a hatch , a boom is rigged in a fore and aft line through its heel . Stresses on the outboard guy will be least if the guy is made fast at a point（）.
A.abreast the heel
B.at right angles to the boom when viewed from above
C.aft of the heel
D.forward of the spiderband
