One day, the cow was eating grass when it began to rain heavily.

一天，牛正在吃草，突然下起了大雨。

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It begins to rain heavily.

开始下大雨了。

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After a little while, it started to rain heavily.

过了一小会，天就开始下大雨了。

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Rain came down heavily a half hour at a time, then pulled back into a silvery sky of fast-moving, fuzzy-bottomed clouds.

NEWYORKER: Outage