| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | once it has be [vb pp] | 71 |
|
| 2 | once it has [been] [vb pp] | 71 |
|
| 3 | once it has been [vb pp] | 71 |
|
| 4 | once it has [be] [vb pp] | 71 |
|
| 5 | once it has [be] established | 6 |
|
