YOU SAID:
I had a nightmare about spiders for many nights
INTO JAPANESE
私は何夜もクモについて悪夢を見ました
BACK INTO ENGLISH
I had nightmares about spiders for many nights
INTO JAPANESE
私は何夜もクモについての悪夢を見ました
BACK INTO ENGLISH
I had nightmares about spiders for many nights
You've done this before, haven't you.