| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must have [vb pp] a | 37 |
|
| 2 | it must have [vb pp] a | 31 |
|
| 3 | it must have taken a | 8 |
|
| 4 | it must have seemed a | 7 |
|
| 5 | it must have [vb pp] an | 6 |
|
| 6 | it must have cost a | 5 |
|
| 7 | it must have had a | 5 |
|
