| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] difficult [noun] | 1182 |
|
| 2 | [adv] difficult [noun sg] | 826 |
|
| 3 | [adv] [adj] period | 499 |
|
| 4 | [adv] [adj] period | 407 |
|
| 5 | [adv] difficult period | 15 |
|
| 6 | [adv] difficult period | 13 |
|
