Sometimes, though, in an attempt to test how firm the floor is, you jump up and down!

但是，有时候，为了检验地板的牢固程度，你还会上下蹦几下！

youdao

Sometimes, though, in an attempt to test how firm the floor is, you jump up and down!

但是，有时候，为了检验地板的牢固程度，你还会上下蹦几下！

youdao