make good time 快速行进；有效利用运行时间

A：Do you always go to work by bus?
B：That’s right.
A：Isn’t it slow to go by bus?
B：Well, a little, even though the bus makes good time, I have to leave a minute margin.

A：你总是乘公共汽车上班吗？
B：对。
A：乘公共汽车不慢吗？
B：有点慢，即使开得很快，我还是得留出20分钟富余时间。