被困在水下是我最可怕的噩梦。

Being trapped underwater is my worst ___nightmare.

整个旅程是一场噩梦——我们丢了行李，还晚到了两天。

The whole journey was a ___nightmare - we lost our luggage and we arrived two days late.

当我必须买点东西时，我通常找不到它，然后购物就变成了一场噩梦。

When I have to buy something, I usually can't find it and then shopping becomes a ___nightmare.