请把花瓶放在架子的最下层。

Please put the vase on the ___bottom shelf.

钥匙掉在了抽屉的最里面。

The keys fell to the ___bottom of the drawer.

尽管他们很努力，但最终还是在比赛中垫底。

Despite their efforts, they ended up at the ___bottom of the competition.

他摔了一跤，屁股着地。

He fell down and landed on his ___bottom.

我们需要找出这个问题的根源才能解决它。

We need to get to the ___bottom of this issue to solve it.