| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must [verb] | 1992 |
|
| 2 | it must [vb infin] | 1990 |
|
| 3 | [pron] must ensure | 126 |
|
| 4 | [pers pn] must ensure | 121 |
|
| 5 | it [modal v] ensure | 51 |
|
| 6 | it must ensure | 6 |
|
| 7 | it must ensure | 6 |
|
