| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] for twenty years | 45 |
|
| 2 | [vb pp] for twenty year | 19 |
|
| 3 | [v-ing] for twenty year | 12 |
|
| 4 | [vb past] for twenty year | 11 |
|
