| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [vb pp] [to-vb] [prep] | 1545 |
|
| 2 | is [vb pp] [to-vb] been | 369 |
|
| 3 | [vb pp] [to-vb] been [prep] | 74 |
|
