| I | crumble |
|---|---|
| you | crumble |
| he/she/it | crumbles |
| we | crumble |
| you | crumble |
| they | crumble |
| I | crumbled |
|---|---|
| you | crumbled |
| he/she/it | crumbled |
| we | crumbled |
| you | crumbled |
| they | crumbled |
| I | have | crumbled |
|---|---|---|
| you | have | crumbled |
| he/she/it | has | crumbled |
| we | have | crumbled |
| you | have | crumbled |
| they | have | crumbled |
| I | had | crumbled |
|---|---|---|
| you | had | crumbled |
| he/she/it | had | crumbled |
| we | had | crumbled |
| you | had | crumbled |
| they | had | crumbled |
单语范例（未经PONS编辑处理）
The temple is crumbling on account of total negligence.
en.wikipedia.org It is known to be found on crumbling shaded rock faces in subtropical forest.
en.wikipedia.org One of them was crumbling down at the top, and in that and another there were only black gaping holes where clock-dials should have been.
en.wikipedia.org The stadium has not been well maintained over the years, and by the start of the 21st century it was actually crumbling.
en.wikipedia.org Some pillars still stand in all their glory but others have crumbled down.
en.wikipedia.org