| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [vb past] [prep] a | 1277 |
|
| 2 | it [vb past] [been] a | 550 |
|
| 3 | it [vb past] [been] [prep] | 331 |
|
| 4 | [vb past] [been] [prep] a | 288 |
|
