大家好，請問一下
wiktionary對how come的用法解釋如下：
"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，說How come雖是疑問句，但詞序是直述句的排列方式。
想問的是，「...in that the word order of the question...」
為何要多用一個that，照理說直接寫in the word order of the question
不就可以了嗎？
加上that的話，我的理解是the word order of the question變成that的同位語，但感覺
好像多一舉。難道是要和後面那個that對襯嗎？
請教一下，謝謝！
https://en.wiktionary.org/wiki/how_come#English