| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] could [be] | 9 |
|
| 2 | [modal v] could [be] | 9 |
|
| 3 | could [modal v] [be] | 8 |
|
| 4 | could could [be] | 7 |
|
