But it seemed that he had disappeared into thin air.

但是他似乎消失得无影无踪了。

She's vanished into thin air.

她在空气中消失了。

I saw he disappear into thin air like vapour.

我看见他像蒸汽一样消失不见了。

The fine thing, always vanishes into thin air.

美好的东西，总是烟消云散。

They stepped on the first step and vanished into thin air.

他们一踩到第一级台阶，就迅速消失在了稀薄的空气之中。