仪表保护接地连接线标识颜色通常为()。
A、绿色
B、黄色
C、兰/绿色
D、黄/绿色
参考答案:A
---Have you called Mr Johnson’s office?
---Yes.He ____back before tomorrow noon.So he can attend our meeting on time.
A.expected
B.is expected
C.is expecting
D.is to expect
经过一点可作( )条直线;如果有3个点,经过其中任意两点作直线,可以作( )条直线。