| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb infin] [be] necessary for | 13 |
|
| 2 | [not/n't] [be] necessary for | 12 |
|
| 3 | [not/n't] [vb infin] [be] necessary | 11 |
|
| 4 | [not/n't] [vb infin] [be] for | 10 |
|
