题干
—Do you think we should accept that offer?
— Yes, we should, for we ___such bad luck up till now, and time __ out.
— Yes, we should, for we ___such bad luck up till now, and time __ out.
A：have had; is running
B：had; is running
C：have; has been ru
D：have had; has been ru
答案(点此获取答案解析）
A
度为v，经过c点时的速度为3v，则ab段与ac段位移之比为( )
