采用步行测速时，人快跑能跟上车组的速度，约为（）km/h。
A.10
B.13
C.15
D.17
参考答案：D
— You haven’t said a word about my new coat, Brenda. Do you like it?
— I’ m sorry I ＿＿ anything about it sooner. I certainly think it’s pretty on you.
A．wasn’t saying
B．don’t say
C．won’t say
D．didn’t say
