| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it have been [prep] [det] | 46 |
|
| 2 | it have been shown [prep] | 34 |
|
| 3 | have been shown [prep] [det] | 18 |
|
| 4 | it have been shown [det] | 6 |
|
