单项选择题
A.your work becoming rounded B.injury to your hand C.overheating of the file D.pinning
Before welding is permitted on a fuel tank, it must be ...
单项选择题Before welding is permitted on a fuel tank, it must be certified or declared （）
A.safe for becoming rounded B.safe for hot work C.not safe for personnel D.not safe for hot work
Safe welding practice requires （）A.checking the area fo...
单项选择题Safe welding practice requires （）
A.checking the area for items that may catch fire B.that a fire watch be posted C.checking for the explosive gases D.all of the above
Which lubricating oil additive is used in diesel engine...
单项选择题Which lubricating oil additive is used in diesel engines to reduce the tendency for sludge and varnish to form on the engine parts?（）
A.Flash point improvers B.Pour point improvers C.Inhibitors D.Foam suppressors
