| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [is] [vb pp] [adv] difficult | 29 |
|
| 2 | is [vb pp] [adv] difficult | 28 |
|
| 3 | [is] made [adv] difficult | 24 |
|
| 4 | [is] [vb pp] more difficult | 17 |
|
