| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it become necessary [to-vb] | 41 |
|
| 2 | it [vb -s] necessary [to-vb] | 30 |
|
| 3 | it [vb past] necessary [to-vb] | 24 |
|
| 4 | it became necessary [to-vb] | 21 |
|
| 5 | it becomes necessary [to-vb] | 17 |
|
| 6 | it seem necessary [to-vb] | 7 |
|
| 7 | it seems necessary [to-vb] | 6 |
|
