| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | which [verb] been [vb pp] for many | 7 |
|
| 2 | which have been [vb pp] for many | 7 |
|
| 3 | which had been [vb pp] for many | 5 |
|
| 4 | which [vb past] been [vb pp] for many | 5 |
|
