| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been caused by a | 33 |
|
| 2 | have been caused [prep] a | 12 |
|
| 3 | to have been caused [prep] a | 9 |
|
| 4 | had been caused [prep] a | 8 |
|
| 5 | has been caused [prep] a | 5 |
|
