| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [conj] [ex0] could have been [det] | 7 |
|
| 2 | [ex0] could [adv] have been [det] | 5 |
|
| 3 | [ex0] could have been [det] [noun] | 10 |
|
| 4 | [ex0] could have been [det] [noun sg] | 9 |
|
