| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [verb] to [art] [adj] | 856 |
|
| 2 | difficulty [prep] [verb] [art] [adj] | 215 |
|
| 3 | difficulty [prep] [verb] to [art] | 18 |
|
| 4 | difficulty [prep] [verb] to [adj] | 9 |
|
| 5 | difficulty [verb] to [art] [adj] | 5 |
|
