| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must [vb infin] | 1990 |
|
| 2 | [adv] must [vb infin] | 443 |
|
| 3 | it [adv] [vb infin] | 330 |
|
| 4 | it [adv] must | 28 |
|
