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1·He had to turnback and gave the boy two pounds.

他必须转回去并且给了男孩二磅。

2·That's why our turnback for setup is 24-48 hours during business days only.

这就是为什么我们的设置滕巴克是在工作24 - 48个小时天。

3·A controlling method of late switch on is put forward, which can reduce the impulse current of linear motor in the turnback period. The reliablity of the controlling method is discussed.

提出了减小电机换向冲击电流的延时通电控制方式，讨论了实现该控制方式的可行性和最佳参数优化。