写绿豆日记的英语作文，你可以遵循以下步骤和结构：

开头

引入主题，例如：“Today is the third day for the mung bean to grow fat!”（今天是我观察绿豆生长的第三天!）

描述绿豆的变化

详细描述绿豆的外观变化，例如：“The mung bean's uniform cannot be put on anymore, it has revealed a white and chubby body with a long '芽' growing out.”（绿豆的“军装”已经穿不上了，露出一个白白胖胖的身体，上面长出了一条长长的“小芽”。）

注意使用形象的比喻和形容词，例如：“The mung bean is very soft. When I pinch this 'uniform', it feels like it's going to fall off.”（绿豆很软，当我捏这个“军装”时，感觉它快要掉下来了。）

记录观察过程

描述你是如何观察绿豆的，例如：“Yesterday, I soaked the mung bean in water and covered it with a cloth. This morning, I removed the cloth and found a little sprout had grown.”（昨天，我把绿豆泡在水里，上面盖了一块布。今天早上，我拿掉布，发现一个小芽已经长出来了。）

表达感受

分享你在观察过程中的感受，例如：“I'm amazed at how quickly the mung bean has grown. It's like watching a magic trick every day.”（我对绿豆快速生长感到惊奇。就像每天在看一场魔术表演。）

结尾

总结观察结果或表达未来的期望，例如：“I'm looking forward to seeing how much the mung bean will grow tomorrow.”（我期待着明天能看到绿豆会长成什么样子。）

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Mung Bean Diary

Today is the third day for the mung bean to grow fat! I'm amazed at how quickly it has grown. The mung bean's uniform cannot be put on anymore； it has revealed a white and chubby body with a long '芽' growing out. The '芽' feels very smooth to the touch.

Yesterday, I soaked the mung bean in water and covered it with a cloth. This morning, I removed the cloth and found a little sprout had grown. It's like watching a magic trick every day. The mung bean is very soft, and when I pinch this 'uniform', it feels like it's going to fall off.

I'm curious to see how much the mung bean will grow tomorrow. I can't wait to observe its progress and document it in my diary.

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希望这个示例能帮助你写出一篇有趣的绿豆日记!