矿物基液压油通常染成的颜色为:().
A.紫色
B.蓝色
C.绿色
D.红色
参考答案:D
在凭证处理中,未经复核的凭证可随时修改。( )
To learn to swim well, ___________.
A.one needs much practice
B.much practice is needed
C.much practice needs
D.one is needed much practice