这是我在一本原文的英文文法书看到的，
问题就是以下节录的这一段:
"Dear Emily,
We leave for Spain in just three weeks! It'll be a great trip
over there because we're stopping in London for five days
before we go on to Madrid."
这是书本内页翻拍照片：
https://imgur.com/BSyD1k8
https://imgur.com/5Ze30y5
问题就出在第一句:
"We leave for Spain in just three weeks!"
因为就目前所学及找到的资料当中，
用现在简单式来表示发生在未来的事情只有几种状况，
像是出现在以"if"或"after"等副词子句当中的动词，
EX: I am going to play after he leaves.
或是表示固定或反复发生的事实，
EX: The train leaves at 10pm.
但"We leave for Spain in just three weeks!"这句似乎不符合上述情况。
感觉用"We are going to leave for .."好像比较合理。
请问是该句有问题，还是我的理解有错呢？
谢谢大家...