未经锻轧加工，按重量计含硅50%、含锌40%、含铬10%的合金锭( ) A．19 B．20 C．21 D．22
参考答案：A—79012000
下肢动脉主干自上而下依次为____、____、____和____。
The book is for us to read.
A．good enough
B．enough good
C．too good
D．good too
