| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [vb pp] [conj] | 11283 |
|
| 2 | [vb pp] [conj] necessary | 184 |
|
| 3 | is [vb pp] necessary | 28 |
|
| 4 | is [conj] necessary | 6 |
|
