| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] have been | 21560 |
|
| 2 | [modal v] have been | 21560 |
|
| 3 | could have [be] | 2545 |
|
| 4 | could have be | 2545 |
|
| 5 | could [verb] been | 2543 |
|
| 6 | could have [been] | 2541 |
|
| 7 | could have been | 2541 |
|
