I left my car in a lay-by and set off on foot.

我把车留在路侧停车带，开始步行。

It was the first time I had set foot on African soil.

那是我第一次踏上非洲大地。

It was the first time I had set foot on American soil.

那是我第一次踏足美洲大地。

In March 1889, she became the first British sovereign to set foot on Spanish soil.

1889年3月，她成为首位踏上西班牙国土的英国君主。

Scarcely had they set foot on the threshold, when Tom called out, "Don't bring me any more hay!"

他们刚一踏进门槛，汤姆就喊道：“别再给我拿草料了！”