| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [verb] been [adv] [adj] when | 9 |
|
| 2 | must [vb infin] be [adv] [adj] when | 9 |
|
| 3 | must have be [adv] [adj] when | 9 |
|
| 4 | must have be [adv] [adj] when | 8 |
|
