单项选择题
A.An economizer B.An attemperator C.A water dram D.A down-comer tube
Upon the completion of required tests, a （） should be p...
单项选择题Upon the completion of required tests, a （） should be placed on each extinguisher, showing the date and the person who completed the tests.
A.cap B.disc C.tag D.cover
If you must enter a room or compartment to combat the f...
单项选择题If you must enter a room or compartment to combat the fire, keep an escape path （）.
A.open B.close C.opens D.closes
According to the international regulations concerning t...
单项选择题According to the international regulations concerning the prevention of pollution of sea areas from ships, the disposal into the sea of all plastics is （）.
A.welcome B.admitted in some special sea areas C.prohibited D.acceptable
