| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] how difficult [pron] [be] for | 20 |
|
| 2 | know how [adj] [pron] [be] for | 15 |
|
| 3 | know how difficult [pron] [be] [prep] | 6 |
|
| 4 | know [Wh adv] difficult [pron] [be] for | 5 |
|
| 5 | know how difficult [pron] [be] for | 5 |
|
| 6 | know [adv] difficult [pron] [be] for | 5 |
|
