| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [vb infin] been [adv] [prep] [noun] | 6 |
|
| 2 | must [vb infin] been [adv] [prep] [noun] | 6 |
|
| 3 | must have been [adv] [prep] [noun] | 6 |
|
| 4 | must [vb infin] been there [prep] [noun] | 5 |
|
