| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [vb mod] be a | 3853 |
|
| 2 | it [modal v] be a | 3853 |
|
| 3 | [pron] must be a | 840 |
|
| 4 | it must be [art] | 347 |
|
| 5 | it must be a | 207 |
|
| 6 | it must [be] a | 207 |
|
