这是一个小村庄，位于河口。

It is a small village, by the ___mouth ___of ___a ___river.

河口狭窄的出口在流入海洋时产生高水压。

The narrow exit at the ___mouth ___of ___a ___river creates high water pressure as it flows into the sea.

河口通常是淡水与盐水混合的丰富生态系统。

The ___mouth ___of ___a ___river is often a rich ecosystem where freshwater mixes with saltwater.