我们坐在门廊最上层的台阶上看日落。

We sat on the top ___step of the porch to watch the sunset.

她在最底下的台阶上绊了一下，钥匙掉了。

She tripped on the bottom ___step and dropped her keys.

走下这些旧台阶时请扶着栏杆。

Please hold the railing when you walk down these old ___steps.