Various kinds of vehicles run to and fro in the street.

　　大街上往來(lái)的車輛很多。

　　He hopped to and fro between London and Paris for the business.

　　為了這筆生意他曾不停地往返于倫敦和巴黎。

　　Your thoughts cannot be tossed to and fro like the waves of the sea.

　　你的思考不能像大海的波浪一樣起伏。