| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is useful for [verb] | 39 |
|
| 2 | useful for [verb] [adv] | 29 |
|
| 3 | is useful [verb] [adv] | 22 |
|
| 4 | is for [verb] [adv] | 9 |
|
