| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must be [vb pp] [prep] | 4919 |
|
| 2 | [pron] must be [vb pp] | 2574 |
|
| 3 | [pron] be [vb pp] [prep] | 472 |
|
| 4 | [pron] must be [prep] | 436 |
|
