| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it is often [verb] [verb] | 15 |
|
| 2 | it is often [vb pp] [verb] | 14 |
|
| 3 | it is often [verb] [to-vb] | 11 |
|
| 4 | it is often used [verb] | 6 |
|
| 5 | it is often use [verb] | 6 |
|
