单项选择题
The line-throwing appliance provided on board ship is().
A.for the saving of life B.for fire-fighting C.for mooring purpose D.for towing purpose
单项选择题 我国的审判机关是()。
问答题 是否在夹具中定位支承点数少于六个就不会出现过定位?
单项选择题 The discharge side of every fire pump must be equipped with a().