| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [be] a [noun] | 8490 |
|
| 2 | must [be] a [noun] | 725 |
|
| 3 | must [prep] [be] a | 18 |
|
| 4 | must [prep] a [noun] | 12 |
|
| 5 | must [prep] [be] [noun] | 7 |
|
