順流而下;
例句
1.It is in this manner that, in the blindness of a poor political economy, we drown and allow to float down stream and to be lost in the gulfs the well-being of all.
由於這樣，壹個盲目而又拙劣的政治經濟學使公眾的福利喪失，付之流水，使它沈沒在深淵中。
2.The logs were knocked together as they floated down the stream.
圓木順流而下時互相碰撞著。