| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | years it have been [verb] | 27 |
|
| 2 | years it have been [vb pp] | 21 |
|
| 3 | years it has been [verb] | 19 |
|
| 4 | years it have been [v-ing] | 6 |
|
| 5 | years it 's been [verb] | 5 |
|
