| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] must be [verb] | 6921 |
|
| 2 | [noun] must be [vb pp] | 6533 |
|
| 3 | [noun] [vb mod] be kept | 549 |
|
| 4 | [noun] [modal v] be kept | 549 |
|
| 5 | [noun] must be keep | 107 |
|
| 6 | [noun] must be kept | 104 |
|
| 7 | [noun] must [be] kept | 104 |
|
| 8 | [noun] must be kept | 104 |
|
| 9 | [noun] must [be] kept | 104 |
|
