| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been [vb pp] for centuries | 32 |
|
| 2 | has been [vb pp] for century | 17 |
|
| 3 | have been [vb pp] for century | 8 |
|
| 4 | had been [vb pp] for century | 6 |
|
