| singular | plural |
| Infinitive | | |
| warn | |
| present simple | | |
| 1 | I warn | we warn |
| 2 | you warn | you warn |
| 3 | he/she/it warns | they warn |
| past simple | | |
| 1 | I warned | we warned |
| 2 | you warned | you warned |
| 3 | he/she/it warned | they warned |
| future simple | | |
| 1 | I will/shall warn | we will/shall warn |
| 2 | you will/shall warn | you will/shall warn |
| 3 | he/she/it will/shall warn | they will/shall warn |
| conditional simple | | |
| 1 | I would warn | we would warn |
| 2 | you would warn | you would warn |
| 3 | he/she/it would warn | they would warn |
| present continuous | | |
| 1 | I am warning | we are warning |
| 2 | you are warning | you are warning |
| 3 | he/she/it is warning | they are warning |
| past continuous | | |
| 1 | I was warning | we were warning |
| 2 | you were warning | you were warning |
| 3 | he/she/it was warning | they were warning |
| future continuous | | |
| 1 | I will be warning | we will be warning |
| 2 | you will be warning | you will be warning |
| 3 | he/she/it will be warning | they will be warning |
| conditional continuous | | |
| 1 | I would be warning | we would be warning |
| 2 | you would be warning | you would be warning |
| 3 | he/she/it would be warning | they would be warning |
| present perfect | | |
| 1 | I have warned | we have warned |
| 2 | you have warned | you have warned |
| 3 | he/she/it has warned | they have warned |
| past perfect | | |
| 1 | I had warned | we had warned |
| 2 | you had warned | you had warned |
| 3 | he/she/it had warned | they had warned |
| future perfect | | |
| 1 | I will have warned | we will have warned |
| 2 | you will have warned | you will have warned |
| 3 | he/she/it will have warned | they will have warned |
| conditional perfect | | |
| 1 | I would have warned | we would have warned |
| 2 | you would have warned | you would have warned |
| 3 | he/she/it would have warned | they would have warned |
