| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun sg] [prep] twenty years ['s] | 7 |
|
| 2 | [noun sg] [prep] twenty years ' | 7 |
|
| 3 | [noun sg] [prep] twenty years ' | 7 |
|
| 4 | [noun sg] of twenty years [unc] | 5 |
|
