| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been [v-ing] [prep] [adj] | 1054 |
|
| 2 | must have been [v-ing] [prep] | 81 |
|
| 3 | must have been [prep] [adj] | 51 |
|
| 4 | must have been [v-ing] [adj] | 22 |
|
