| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must [be] [vb pp] | 1391 |
|
| 2 | must [not/n't] [be] [vb pp] | 544 |
|
| 3 | it must [not/n't] [be] | 106 |
|
| 4 | it [not/n't] [be] [vb pp] | 19 |
|
