| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [not/n't] [verb] [that] | 553 |
|
| 2 | is difficult [verb] [that] | 97 |
|
| 3 | is difficult [not/n't] [verb] | 29 |
|
| 4 | difficult [not/n't] [verb] [that] | 8 |
|
