To lie down in English, you can say "to lie down" or "to recline." This phrasing comes from the verb "to lie," which means "to rest or be in a horizontal position" or "to be situated or located." Here are some example sentences:

I need to lie down and rest for a while.

She reclined on the couch and closed her eyes.

The cat likes to lie in the sun.

The city is located on the east coast.

In Chinese, "趴下" (pā xià) means "to lie down" or "to recline."