| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] have been [v-ing] [prep] | 1813 |
|
| 2 | [noun] must have been [v-ing] | 82 |
|
| 3 | must have been [v-ing] [prep] | 81 |
|
| 4 | [noun] must have been [prep] | 77 |
|
