| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be useful for [v-ing] | 99 |
|
| 2 | [be] useful for [v-ing] | 99 |
|
| 3 | [is] useful for [v-ing] | 40 |
|
| 4 | is useful for [v-ing] | 39 |
|
| 5 | [am/are] useful for [v-ing] | 29 |
|
| 6 | are useful for [v-ing] | 28 |
|
| 7 | be useful for [v-ing] | 23 |
|
| 8 | [be] useful for [v-ing] | 23 |
|
| 9 | [be] useful for keeping | 6 |
|
