Present
| I | crumble |
| You | crumble |
| She | crumbles |
| We | crumble |
| They | crumble |
Past
| I | crumbled |
| You | crumbled |
| She | crumbled |
| We | crumbled |
| They | crumbled |
Perfect
| I | have | crumbled |
| You | have | crumbled |
| She | has | crumbled |
| We | have | crumbled |
| They | have | crumbled |
Future
| I | will | crumble |
| You | will | crumble |
| She | will | crumble |
| We | will | crumble |
| They | will | crumble |
Past Perfect
| I | had | crumbled |
| You | had | crumbled |
| She | had | crumbled |
| We | had | crumbled |
| They | had | crumbled |
Future Perfect
| I | will | have | crumbled |
| You | will | have | crumbled |
| She | will | have | crumbled |
| We | will | have | crumbled |
| They | will | have | crumbled |
Present - Conditional
| I | would | crumble |
| You | would | crumble |
| She | would | crumble |
| We | would | crumble |
| They | would | crumble |
Perfect - Conditional
| I | would | have | crumbled |
| You | would | have | crumbled |
| She | would | have | crumbled |
| We | would | have | crumbled |
| They | would | have | crumbled |