| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [be] a [adj] | 4979 |
|
| 2 | must [be] a [adj] | 406 |
|
| 3 | must [prep] [be] [adj] | 16 |
|
| 4 | must [prep] [be] a | 16 |
|
