热水杯上方升起的水蒸气在寒冷的空气中清晰可见。

The ___vapour rising from the hot cup was clearly visible in the cold air.

当水加热时，会产生蒸汽。

When water is heated, it produces ___vapour.

那些谣言就像蒸汽一样消散了，毫无实质内容。

Those rumors were just ___vapor, disappearing without any substance.