| Simple | Progressive | Perfect | Progressive |
| Present |
| I strengthen |
| you strengthen |
| he/she/it strengthens |
| we strengthen |
| you all strengthen |
| they strengthen |
|
| I am strengthening |
| you are strengthening |
| he/she/it is strengthening |
| we are strengthening |
| you all are strengthening |
| they are strengthening |
|
| I have strengthened |
| you have strengthened |
| he/she/it has strengthened |
| we have strengthened |
| you all have strengthened |
| they have strengthened |
|
| I have been strengthening |
| you have been strengthening |
| he/she/it has been strengthening |
| we have been strengthening |
| you all have been strengthening |
| they have been strengthening |
|
| Past |
| I strengthened |
| you strengthened |
| he/she/it strengthened |
| we strengthened |
| you all strengthened |
| they strengthened |
|
| I was strengthening |
| you were strengthening |
| he/she/it was strengthening |
| we were strengthening |
| you all were strengthening |
| they were strengthening |
|
| I had strengthened |
| you had strengthened |
| he/she/it had strengthened |
| we had strengthened |
| you all had strengthened |
| they had strengthened |
|
| I had been strengthening |
| you had been strengthening |
| he/she/it had been strengthening |
| we had been strengthening |
| you all had been strengthening |
| they had been strengthening |
|
| Future |
| I will strengthen |
| you will strengthen |
| he/she/it will strengthen |
| we will strengthen |
| you all will strengthen |
| they will strengthen |
|
| I will be strengthening |
| you will be strengthening |
| he/she/it will be strengthening |
| we are strengthening |
| you all will be strengthening |
| they will be strengthening |
|
| I will have strengthened |
| you will have strengthened |
| he/she/it will have strengthened |
| we will have strengthened |
| you all will have strengthened |
| they will have strengthened |
|
| I will have been strengthening |
| you will have been strengthening |
| he/she/it will have been strengthening |
| we will have been strengthening |
| you all will have been strengthening |
| they will have been strengthening |
|
