她昨晚做了一个可怕的噩梦，梦见自己被怪物追赶。

She had a terrifying ___nightmare last night about being chased by monsters.

昨晚的航班延误简直是一场噩梦。

The flight delay last night was a complete ___nightmare.

每次考试前他都觉得那是一场噩梦。

Every exam feels like a ___nightmare to him.