| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] difficult for [pron] [to-vb] | 65 |
|
| 2 | difficult for [pron] [to-vb] [prep] | 41 |
|
| 3 | [pron] for [pron] [to-vb] [prep] | 15 |
|
