| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [verb] for several years | 30 |
|
| 2 | be [vb pp] [prep] several years | 24 |
|
| 3 | been [verb] [prep] several years | 20 |
|
| 4 | be [v-ing] [prep] several years | 15 |
|
| 5 | be [verb] [prep] several years | 11 |
|
| 6 | be [verb] over several years | 8 |
|
