运动时，放面镜子在前面，单单自己的感觉有时候不很准确，所以这个很重要。

Use a mirror - the feeling of motion you get while exercising can be very deceptive, so this is important.

youdao

运动时，放面镜子在前面，单单自己的感觉有时候不很准确，所以这个很重要。

Use a mirror - the feeling of motion you get while exercising can be very deceptive, so this is important.

youdao