| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | been [adv] [verb] [prep] recent years | 21 |
|
| 2 | been [adv] [verb] in recent years | 20 |
|
| 3 | been [adv] [vb pp] [prep] recent years | 19 |
|
| 4 | been extensively [verb] [prep] recent years | 6 |
|
| 5 | been extensively [verb] [prep] recent years | 6 |
|
