| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] how difficult it [is] for | 13 |
|
| 2 | [vb base] how difficult it [is] for | 7 |
|
| 3 | know how difficult it [is] for | 5 |
|
| 4 | know how difficult it [is] for | 5 |
|
| 5 | how difficult it [is] for [noun] | 8 |
|
| 6 | how difficult it [is] for [noun pl] | 6 |
|
