单项选择题
A.exposure limits B.concentration limits C.threshold limit values D.substance limit values
Storage batteries should be charged in a well ventilate...
单项选择题Storage batteries should be charged in a well ventilated area because（）.
A.they generate heat B.they emit hydrogen C.of the toxic fumes they emit D.they recharge faster in a well ventilated space
One of the principal dangers inherent in liquefied petr...
单项选择题One of the principal dangers inherent in liquefied petroleum gas is（）.
A.as it warms up it becomes heavier than air B.the way it reacts with sea water C.the strong odor it produces D.its low temperature causes frostbite or freezing
Name one major advantage of transporting gas under refr...
单项选择题Name one major advantage of transporting gas under refrigeration.（）
A.It increases its volume B.It reduces its volume C.It has less product per volume D.None of the above
