The constantcirculation means no refueling interruptions.
这个持续不断的循环意味着没有因补充燃料而中断。
2
Thus, there is constantcirculation of oil between the pan and the working parts of the engine.
因而在油底壳和发动机工作零件之间有机油不断流动循环。
3
This circulation gets moreor less switched off at night when the temperature gradients disappear or reverse, avoiding heat loss and keeping the nest at a roughly constant temperature.