他常常沉浸在成为宇航员的幻想中。

He often gets lost in a ___fantasy of becoming an astronaut.

她最喜欢写关于龙和魔法的幻想故事。

She loves writing ___fantasy stories about dragons and magic.

她幻想一夜暴富的念头只是个不切实际的空想。

Her ___fantasy of getting rich overnight is just an unrealistic dream.