| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] is necessary [prep] | 209 |
|
| 2 | [det] [pron] is [prep] | 166 |
|
| 3 | [det] [pron] is necessary | 24 |
|
| 4 | [det] is necessary [prep] | 17 |
|
