英语作文中提建议的句型可分为以下五类，结合权威资料整理如下：
一、固定句型结构
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"It is high time..."
该句型强调建议的紧迫性，例如：
It is high time that we put an end to the waste of resources.
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"There is no doubt that..."
用于强调建议的必要性，例如：
There is no doubt that we must improve our study methods.
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"Only in this way can we..."
表示唯一解决方案，例如：
Only in this way can we achieve sustainable development.
二、常用表达方式
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虚拟语气结构
As if/though he were...（如：He spoke as if he were a foreigner.）
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建议动词短语
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should/ought to+动词原形（如：You should study harder.）
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advise+不定式（如：I advise you to review your notes.）
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三、委婉表达技巧
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"What about..."/...？ "How about..."
用于提出建议，例如：
What about going for a walk in the park？
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"How can we..."
强调合作性建议，例如：
How can we improve our team communication？
四、强调必要性或紧迫性
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The time is long overdue for us to...（如：The time is long overdue for us to adopt new technologies.）
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We must realize that...（如：We must realize the importance of environmental protection.）
五、注意事项
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避免使用命令式语气，优先选择委婉表达（如用"should"而非"must"）
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结合具体场景选择句型，例如正式场合多用"It is high time..."，日常交流可用"What about..."