| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [adj] to ensure [conj] [adj] [noun pl] | 17 |
|
| 2 | be necessary [verb] [conj] [adj] [noun pl] | 10 |
|
| 3 | be necessary [to-vb] [conj] [adj] [noun pl] | 10 |
|
| 4 | be necessary to ensure [conj] [adj] [noun] | 8 |
|
| 5 | be necessary ensure [conj] [adj] [noun pl] | 6 |
|
| 6 | [be] necessary to ensure [conj] [adj] [noun pl] | 6 |
|
