| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is essential [prep] [v-ing] | 39 |
|
| 2 | is essential [prep] [verb] | 39 |
|
| 3 | is essential for [verb] | 20 |
|
| 4 | is essential in [verb] | 9 |
|
| 5 | is essential to [verb] | 9 |
|
| 6 | is essential [prep] understand | 6 |
|
| 7 | is essential [prep] understanding | 6 |
|
