| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have [been] shown to be | 176 |
|
| 2 | have been shown to be | 176 |
|
| 3 | has [been] shown to be | 100 |
|
| 4 | have [been] shown to be | 62 |
|
| 5 | had [been] shown to be | 13 |
|
