| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | which can be [vb pp] back to | 9 |
|
| 2 | which can be [vb pp] back to | 9 |
|
| 3 | which can be [vb pp] back to | 9 |
|
| 4 | which can be [vb pp] back to | 9 |
|
| 5 | which can be traced back to | 7 |
|
