这两条河流在下游汇合成一条更大的河流。

The two rivers ___merge into a larger one downstream.

两条小路在森林深处逐渐合并成一条。

The two paths ___merge into one deep in the forest.

在高速公路交汇处，车辆需要并入主车道。

At the highway junction, vehicles need to ___merge into the main lane.