Speaker A: I think women are much better drivers than men.Speaker B: ______

A．You are right. They drive slowly and this makes other drivers behind them very impatient.

B．I certainly agree that men learn to drive more quickly than men.

C．I'll say. They don't get as impatient as men when they drive.

D．Don't mention it. Men have a quicker response than women while driving.

混凝土振捣每处振捣延续时间宜为20~30s，以混凝土不再沉落，不出现气泡，表面呈现浮浆为度，防止（）。