| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | problem that [vb mod] [verb] | 98 |
|
| 2 | [noun] that [vb mod] occur | 88 |
|
| 3 | problem [conj] [vb mod] occur | 12 |
|
| 4 | problem that [modal v] occur | 12 |
|
