| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [conj] [pron] is necessary [verb] | 174 |
|
| 2 | [conj] [pron] is often [verb] | 86 |
|
| 3 | [pron] is often necessary [verb] | 21 |
|
| 4 | [conj] [pron] is often necessary | 6 |
|
