| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] have [been] | 21560 |
|
| 2 | [vb mod] have [been] | 21560 |
|
| 3 | may have [be] | 2874 |
|
| 4 | may [verb] [been] | 2865 |
|
| 5 | may have [been] | 2865 |
|
