| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be useful [subord] the [noun sg] | 18 |
|
| 2 | is useful [subord] [art] [noun sg] | 12 |
|
| 3 | be useful if [art] [noun sg] | 8 |
|
| 4 | be useful when [art] [noun sg] | 7 |
|
| 5 | be useful [subord] [art] [noun sg] | 6 |
|
