请你从头再来一遍吧—我还是搞不清楚。

Can you start from the beginning again—I'm in a muddle.

《牛津词典》

从头再来一遍，准备好后便开始。

Take it from the top and start when you're ready.

youdao

咱们从头再来一遍，看看是否这次能做对。

Let's start over and see if we can get it right this time.

youdao

If you were asking questions, like, how high does it go, but you don't ask when does it go to the highest point, then you don't have to go through the whole process of finding the time at which it turned around.

如果你想问,例如,它可以到多高,不过你并没有问它何时达到最高点,那么你不用从头到尾再来一遍,来弄清质点何时转向

耶鲁公开课 - 基础物理课程节选