| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be to ensure [conj] [adj] [noun pl] | 24 |
|
| 2 | be necessary [conj] [adj] [noun pl] | 15 |
|
| 3 | be necessary to ensure [conj] [adj] | 11 |
|
| 4 | necessary to ensure [conj] [adj] [noun pl] | 8 |
|
