| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] the past twenty years [pers pn] | 6 |
|
| 2 | [prep] the past twenty years [pers pn] | 6 |
|
| 3 | the past twenty years [pers pn] [verb] | 6 |
|
| 4 | the past twenty years [pers pn] have | 6 |
|
