Present
| I | strengthen |
| You | strengthen |
| She | strengthens |
| We | strengthen |
| They | strengthen |
Past
| I | strengthened |
| You | strengthened |
| She | strengthened |
| We | strengthened |
| They | strengthened |
Perfect
| I | have | strengthened |
| You | have | strengthened |
| She | has | strengthened |
| We | have | strengthened |
| They | have | strengthened |
Future
| I | will | strengthen |
| You | will | strengthen |
| She | will | strengthen |
| We | will | strengthen |
| They | will | strengthen |
Past Perfect
| I | had | strengthened |
| You | had | strengthened |
| She | had | strengthened |
| We | had | strengthened |
| They | had | strengthened |
Future Perfect
| I | will | have | strengthened |
| You | will | have | strengthened |
| She | will | have | strengthened |
| We | will | have | strengthened |
| They | will | have | strengthened |
Present - Conditional
| I | would | strengthen |
| You | would | strengthen |
| She | would | strengthen |
| We | would | strengthen |
| They | would | strengthen |
Perfect - Conditional
| I | would | have | strengthened |
| You | would | have | strengthened |
| She | would | have | strengthened |
| We | would | have | strengthened |
| They | would | have | strengthened |