| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [be] common for | 91 |
|
| 2 | it be common for | 91 |
|
| 3 | it [is] common for | 62 |
|
| 4 | it is common for | 61 |
|
| 5 | it [was/were] common for | 28 |
|
| 6 | it was common for | 28 |
|
