垫底 (diàn dǐ): ใส่ sth ที่ด้านล่าง

Before steaming the buns, Mom first lined the bottom of the steamer with a layer of cabbage leaves so they wouldn't stick.

When moving, the workers put some old clothes at the bottom of the box as padding to prevent the porcelain from being shattered by shocks.

This bookshelf is a bit unstable. Dad put a wooden board under it as a base, and the table no longer wobbles.

To keep the cake from sticking to the baking pan, she lined the pan with a layer of parchment paper before pouring in the batter.

He placed a paper napkin under the bowl before setting the hot soup on it, to avoid damaging the tabletop with heat.