Find a straight stick and put it in the ground in a place where you can mark its shadow.

①找一个直棍，将其立在一个你可以标记它的影子的地方。

youdao

Find a straight stick and put it in the ground in a place where you can mark its shadow.

①找一个直棍，将其立在一个你可以标记它的影子的地方。

youdao