大家好，请问一下
wiktionary对how come的用法解释如下：
"How come" differs from "why" in that the word order of the question is the
same as that of a statement. Compare:
You didn't leave. (statement)
How come you didn't leave?
Why didn't you leave?
意思大概懂，说How come虽是疑问句，但词序是直述句的排列方式。
想问的是，“...in that the word order of the question...”
为何要多用一个that，照理说直接写in the word order of the question
不就可以了吗？
加上that的话，我的理解是the word order of the question变成that的同位语，但感觉
好像多一举。难道是要和后面那个that对衬吗？
请教一下，谢谢！
https://en.wiktionary.org/wiki/how_come#English