Question

it was suddenly raining outside when we set off这句英文的语法有错误吗？

Answer 1

语法没啥错误也不是问题，用词不当而已,修改：
it was suddenly raining when we settle down.

追问

我想说的是当我们要出发时，外面突然下雨了 settle down不是定居吗 see off 是出发把

追答

我误解了，所以说是用词不当，造句： It was suddenly raining when we started to go.

Thank you!