The purpose of protothreads is to implement sequential flow of control without using complex state machines or full multi-threading. 它的主要作用是执行顺序控制流，而无须复杂的状态机或者多线程。
The downhole stabilizer location adjuster, fixed between the bit and the drill collar, is a special tool for continual deviation control of a slant hole. 井下稳定器安放位置调节器是斜井旋转钻井时实施井斜连续控制的专用工具，安装在钻头与钻铤之间。
The automatic washing machine is a familiar example of a sequential control system. 自动洗衣机是一个时序控制系统的一个熟悉的例子。
