| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it is difficult for [art] | 31 |
|
| 2 | it is difficult for [art] | 31 |
|
| 3 | it is difficult for the | 19 |
|
| 4 | it is difficult for the | 19 |
|
| 5 | it is difficult for a | 12 |
|
| 6 | it is difficult for a | 9 |
|
