液压挖掘机的回转机构主要采用机械元件传动。
参考答案:错
—Do you think there are ________ new words in this passage?
—Yes,that’s right. I’ll ________ first.
A.too much,look them up
B.too many,look up them
C.much too,look them up
D.too many,look them up
60kg/m钢轨轨头侧面有坡度,该坡度是()。
A.1:40
B.1:20
C.1:16
D.1:10