| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] is useful for [verb] | 10 |
|
| 2 | [pron] is useful for [v-ing] | 10 |
|
| 3 | which is useful for [verb] | 6 |
|
| 4 | which is useful for [verb] | 6 |
|
| 5 | [Wh det] is useful for [verb] | 6 |
|
