我猜你問了兩個問題
引述《howisfashion (台北趙默笙)》之銘言：
: 請問一下..
: 我想表達(意涵)"(非特定)流行是如何形成的"?
: 是不是how is fashion?! 還是"fashion"前仍要加"the"?!
其實有個片語
Come into fashion = to become stylish or fashionable
所以依您的問題，如果要寫出疑問句，或許可以寫成：
How is this _____ come into fashion?
How this ____ become stylish ?
: 上電子字典查了兩個例句:
您 4不4要問 as ... as...的用法
為您查詢到了這個解說
我覺得還蠻清楚的
https://cambridgetaipei.pixnet.net/blog/post/222559349-【英語文法小教室】as...
as-的比較用法四大歸
: as rich as Alexander (此時"as"為 adv.)
: He has earned as much money as I have.(此時"as"為pron.，why?!)
這應該是 He has earned as much money as I do( =earn money). 吧？
: 我是不是可以說 as crazy as your possible，
: (那麼此時的as又是什麼詞性ㄋ?!)
as .... as .... 前面的as 為「副詞」， 後面的是附屬連接詞 + 主詞 + be動詞/助動
詞
所以這句應該是 as crazy as you are
你可以想成是兩句子的合併
you are crazy.
he is crazy as well.
- he is as (副詞） + crazy + as （附屬連接詞）+ you are.
as + 形容詞 / 副詞 as possible. 是另一個片語
表達「盡可能地......」
可以參考這一篇的說明
https://jim652012.pixnet.net/blog/post/18094112
希望有解答到你的疑問