| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] have been [v-ing] [prep] | 1813 |
|
| 2 | [noun] could have been [prep] | 32 |
|
| 3 | could have been [v-ing] [prep] | 31 |
|
| 4 | [noun] could have been [v-ing] | 18 |
|
