There was not one single crack that would let rain come in.

没有一条裂缝能让雨水进来。

At first the light shone through a single crack in the concrete, but over time the floor began to fracture.

起初，光线穿过混凝土上的一条裂缝，但随着时间的推移，地板开始破裂。

These are volcanoes so explosive that they burst open in a single big crack, leaving behind a vast hole, the caldera.

这些火山的爆发力如此之强， 以至于它们在一个大裂缝中爆裂， 留下一个巨大的洞， 即火山口。