| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it was [adj] | 23603 |
|
| 2 | it be necessary | 1964 |
|
| 3 | it [be] necessary | 1964 |
|
| 4 | [pron] was necessary | 493 |
|
| 5 | it [was/were] necessary | 431 |
|
