单项选择题
The gauge pressure inside a container is -0~5kg/cm2, then what is the absolute pressure exerted to the inside surface of thin container?（）
A.0~05Mpa B.0~95Mpa C.1~05Mpa D.0~5Mpa
单项选择题 The crane jib is raised and lowered by means of （）
单项选择题 Which one of three elements for a fire on a tanker vessel is most difficult to eliminate (isolate)?（）
单项选择题 Which system(s) in the hydraulic systems of crane always hold(s) single side of load?（）
