警察逐渐包围了示威者。

Police ___closed ___in on the demonstrators.

敌军正在逼近我们的阵地。

The enemy is ___closing ___in on our position.

随着狼群开始嚎叫，黑暗逐渐笼罩下来。

Darkness ___closed ___in as the wolves began to howl.