| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [adj] [prep] [noun sg] [verb] | 190 |
|
| 2 | be essential [prep] [noun sg] [verb] | 22 |
|
| 3 | [be] essential [prep] [noun sg] [verb] | 22 |
|
| 4 | is essential [prep] [noun] [verb] | 18 |
|
| 5 | [is] essential [prep] [noun sg] [verb] | 13 |
|
