| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have [be] [verb] | 1154 |
|
| 2 | [vb mod] have [be] [v-ing] | 1003 |
|
| 3 | [modal v] have [be] [v-ing] | 1003 |
|
| 4 | could [verb] [be] [v-ing] | 105 |
|
| 5 | could have [be] [v-ing] | 93 |
|
