| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [verb] for | 36 |
|
| 2 | must have been [verb] for | 36 |
|
| 3 | must [vb infin] been [verb] for | 36 |
|
| 4 | must [verb] been [v-ing] for | 18 |
|
| 5 | must [verb] been [vb pp] for | 18 |
|
| 6 | must [verb] been looking for | 5 |
|
| 7 | must [verb] been look for | 5 |
|
