| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [verb] a certain | 14 |
|
| 2 | is [verb] [art] certain | 14 |
|
| 3 | is [verb] a certain | 14 |
|
| 4 | is [v-ing] [art] certain | 7 |
|
