| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] what [pers pn] must [vb infin] be | 6 |
|
| 2 | [prep] what [pers pn] must [vb infin] [been] | 5 |
|
| 3 | [prep] what it must [vb infin] [be] | 5 |
|
| 4 | [prep] what [pers pn] must [vb infin] been | 5 |
|
| 5 | [prep] what [pers pn] must have [be] | 5 |
|
