| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] shown [prep] be essential | 5 |
|
| 2 | be shown [prep] be essential | 5 |
|
| 3 | shown [prep] be essential [prep] | 5 |
|
| 4 | shown [prep] be essential [prep] | 5 |
|
