| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] been [v-ing] [prep] several years | 14 |
|
| 2 | have been [v-ing] [prep] several years | 14 |
|
| 3 | [vb past] been [v-ing] [prep] several years | 6 |
|
| 4 | [vb base] been [v-ing] [prep] several years | 6 |
|
| 5 | had been [v-ing] [prep] several years | 5 |
|
