1. This pressure must be under control, and we control it by means of the mud which we circulate down the drill pipe.
    这种压力必须加以控制，我们让泥桨顺着钻杆向下循环，用这种方法来控制压力。

2. Customers — some dressed in work clothes, some in expensive suits and overcoats — circulate among the counters and stare at shelf after shelf of roses in more than 50 colors.
    顾客们有的身着工装，有的身着昂贵的西服和外套，他们在店内的柜台间走动，一架一架地浏览50多种颜色的玫瑰。