bubble

水沸腾时开始冒泡。

The water started to ___bubble as it boiled.

烧杯中的混合物开始剧烈冒泡。

The mixture in the beaker began to ___bubble vigorously.

他们生活在一个与外界隔绝的小圈子里。

They live in a small ___bubble, isolated from the outside world.