A: Watch your step as you cross the doorsill.
A：跨过门槛时小心脚下。

B: I saw a small flower growing near the doorsill.
B：我看到门槛旁边长着一朵小花。

1) 门槛

2) 门口的台阶

3) 门框底部的横梁

1. 门槛

noun

1. The bottom part of a doorway, typically a piece of wood or stone.

Synonym: threshold