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