| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] be [vb pp] [prep] | 74300 |
|
| 2 | could be [verb] [prep] | 7290 |
|
| 3 | could [be] [vb pp] [prep] | 7114 |
|
| 4 | could be [vb pp] [prep] | 7114 |
|
