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