Everyone ran for cover when it started to rain.

雨下起来时，大家都跑着找地方避雨。

《牛津词典》

The sky suddenly went dark and it started to rain.

天空骤然转暗，随即下起雨来。

《牛津词典》

If it started to rain, she would share her umbrella with me, and I would get to see the underside of a toadstool for the very first time!

假若下起雨来，她会与我共撑一把伞，我就可以第一次看到伞菌的底部！

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"It started to rain really hard in the evening, and began to flood, " said Augustina Garcia Orsi, a 25-year-old student.

NPR: Argentina: Flooding From Torrential Rains Kill 52

It's just started to rain a little bit outside, but I've got my coat and umbrella.

ENGADGET: Hello, I must be going

It seemed that the Finn would make it four straight Spa wins until the rain started to fall in the closing stages and Hamilton homed in.

CNN: How the F1 title was won: Part three