| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [be] necessary | 1964 |
|
| 2 | it be necessary | 1964 |
|
| 3 | it be [adj] | 534 |
|
| 4 | it be [adj] | 403 |
|
| 5 | [pron] be necessary | 23 |
|
| 6 | it be necessary | 23 |
|
| 7 | it [be] necessary | 23 |
|
