出学校大门用英文怎么说

"to leave school" 或 "to exit school" 是表示从学校出门的常用说法。

来源：

leave 是动词，意思是离开或离开某处。
exit 是名词，意思是出口。

英文例句及中文翻译：

I'm leaving school now. 我现在要离开学校了。
Can you wait for me at the school exit? 你能在学校出口等我吗？
Students were seen leaving the school grounds. 学生们被看到离开了学校。
The school exit is located at the back of the building. 学校的出口位于建筑物的后面。