运输机械的类型可分成输送机械和给料机械两种。（）
参考答案：错
什么是社会心理危险源
Which is a distress signal? （）
A.A triangular flag above or below a ball
B.The International Code Signal of distress indicated by "JV"
C.A green smoke signal
D.Flames on the vessel as from a burning tar barrel
