| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] [vb infin] had to be | 50 |
|
| 2 | [modal v] have had to be | 50 |
|
| 3 | [vb mod] [verb] had to be | 50 |
|
| 4 | [modal v] have had to be | 49 |
|
| 5 | would [verb] had to be | 47 |
|
| 6 | would [verb] had to be | 45 |
|
