| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] [verb] [vb pp] a | 2440 |
|
| 2 | [verb] [vb pp] a problem | 115 |
|
| 3 | [modal v] [verb] a problem | 67 |
|
| 4 | [modal v] [verb] [vb pp] problem | 6 |
|
