| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | they must have been [adj] | 28 |
|
| 2 | they must have been [adj] | 28 |
|
| 3 | they must [vb infin] been [adj] | 28 |
|
| 4 | they must [verb] been [adj] | 27 |
|
| 5 | they must [verb] been [adj] | 23 |
|
