| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] could it have [vb pp] | 11 |
|
| 2 | how could it have [vb pp] | 10 |
|
| 3 | [Wh adv] could it have [vb pp] | 10 |
|
| 4 | how could it have [vb pp] | 10 |
|
| 5 | could it have be [vb pp] | 5 |
|
| 6 | could it have [be] [vb pp] | 5 |
|
| 7 | could it have [been] [vb pp] | 5 |
|
| 8 | could it have been [vb pp] | 5 |
|
