| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it is [adv] uncommon for | 55 |
|
| 2 | it is not uncommon for | 53 |
|
| 3 | it is [not/n't] uncommon for | 53 |
|
| 4 | it is not uncommon for | 51 |
|
