ring n.戒指；环；圈；拳击场；马戏场；帮派n.铃声；钟声；电话；口气v.包围；环绕；形成圈v.打电话；回响；鸣响；按铃；听上去
双语例句
The circular mountain on the moon is very famous, and is the keystone of the scientists' research. 这座月球上的环形山很有名，是科学家研究的重点。
Since no other volcano lava or pozzolana are found nearby, so we may exclude the possibility that ringed mountains are volcano craters. 而由于相关地带没有发现火山熔岩或火山灰分布，可以排除环形山是火山口的可能。
