她弯下腰捡起了地上的钥匙。

Tā wān xià yāo jiǎn qǐ le dìshang de yàoshi.

She bent down and picked up the keys from the ground.

坐太久了，我的腰有点酸。

Zuò tài jiǔ le, wǒ de yāo yǒudiǎn suān.

I've been sitting too long; my lower back is a bit sore.

这条裙子的腰有点紧，你试试大一号的。

Zhè tiáo qúnzi de yāo yǒudiǎn jǐn, nǐ shìshi dà yī hào de.

The waist of this skirt is a bit tight; try one size bigger.