| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it be essential [that] [adj] [adj] | 6 |
|
| 2 | it is essential [that] [adj] [adj] | 6 |
|
| 3 | it [is] essential [that] [adj] [adj] | 6 |
|
| 4 | it [be] essential that [adj] [adj] | 6 |
|
