| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is known to be | 130 |
|
| 2 | are known to be | 98 |
|
| 3 | was known to be | 73 |
|
| 4 | were known to be | 41 |
|
| 5 | been known to be | 12 |
|
| 6 | be known to be | 9 |
|
