"It's a dream" 用英语说是 "It's a dream"，来源是英语中表示“这是一个梦”的常用表达。
例句1:
It's just a dream, don't worry about it.
（这只是一个梦，不要担心。）
例句2:
I had a strange dream last night, but I can't remember it now.
（昨晚我做了一个奇怪的梦，但现在我记不起来了。）
例句3:
Sometimes, I wish this was just a dream and I could wake up from it.
（有时，我希望这只是一个梦，我可以从中醒来。）