The sky is dark, so it may rain soon.

天空很暗，所以可能很快下雨。

同一单元的其他句子

• It is raining outside, so take an umbrella.外面正在下雨，所以带把伞。
• The weather is cloudy and windy today.今天天气多云且有风。
• Is it sunny in Beijing now?北京现在阳光明媚吗？
• Don't forget to wear a raincoat in the rain.下雨时别忘了穿雨衣。
• The children are playing in the rain happily.孩子们正在雨中开心地玩耍。