As if 文法

I sat straight up as if I had just experienced a nightmare/
as if having just experienced a nightmare/
as if from a nightmare.
三個都可
你應該是要寫小說之類的吧（看那句子...）
第三個較適合

I see nothing wrong with:

I sat straight up as if just experienced a nightmare.
I sat straight up as if had just experienced a nightmare.
I sat straight up as if just had a nightmare.

as if 後面通常接子句
所以那個網友是對的~
PS: She opened her lips as if (she was going) to speak. 後面也可以接不定詞

I sat straight up as if I had just experienced a nightmare.
較早發生的事放在句子後面時，動詞應用過去完成式，表示比在前面的主要子句的過去簡單式動詞的時間較早。

as if，是<副詞><連接詞>，引導<副詞子句 > 。<子句>中，可用現在式，以表示事實；也可用過去式或<過去完成式>，分別表示與現在或過去事實相反的<假設語氣>。

子句，應有主詞 。故你外國網友說這句應改成
I sat straight up as if I just experienced a nightmare .
網友是否正確？


正確!!