| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | but [pers pn] is not necessary [verb] | 7 |
|
| 2 | but [pers pn] is not necessary [to-vb] | 7 |
|
| 3 | but it is not necessary [verb] | 7 |
|
| 4 | but [pers pn] is not necessary [verb] | 7 |
|
