描述自然现象的句型 — 英语选择题
题目
观察发现：暖空气上升后会冷却，并形成云。选择能准确描述这一自然现象的句子。 A. When warm air rises, it cools and forms clouds. B. When warm air rise, it cools and forms clouds. C. When warm air rises, it cool and forms clouds. D. When warm air rises, it cooled and forms clouds.