基本形式

– 动词原形：warn

– 第一人称单数：warn

– 第一人称复数：warn

– 第三人称单数：warns

– 第二人称单数和复数：warn

时态

– 现在时：warns, warn

– 过去时：warned

– 过去分词：warned

– 现在完成时：has warned, have warned

– 现在完成进行时：have been warning, has been warning

– 过去完成时：had warned

– 将来时：will warn

– 将来完成时：will have warned

– 将来完成进行时：will have been warning

语态

– 及物动词（主动语态）：They warned me about the storm.

– 被动语态：I was warned about the storm.

句型结构

1. 简单句：

– They warn about the risks.

– The risks are warned about.

2. 复合句：

– They warned me that the road was closed.

– I was warned that the road was closed by them.

3. 疑问句：

– Do they warn about the risks?

– Are the risks warned about?

4. 否定句：

– They do not warn about the risks.

– The risks are not warned about.

表格

| 时态 | 主动语态 | 被动语态 |

||-|-|

| 现在时 | They warn | They are warned |

| 过去时 | They warned | They were warned |

| 现在完成时 | They have warned | They have been warned |

| 过去完成时 | They had warned | They had been warned |

| 将来完成时 | They will have warned | They will have been warned |

| 现在时进行时 | They are warning | They are being warned |

| 过去时进行时 | They were warning | They were being warned |

| 将来时进行时 | They will be warning | They will be being warned |

通过上述表格，你可以快速地回顾和记忆 “warn” 的各种用法。记住，这些用法可以根据具体的语境和句子结构进行适当的调整。