| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [is] [adv] used for | 148 |
|
| 2 | [adv] used for [v-ing] | 99 |
|
| 3 | [is] used for [v-ing] | 44 |
|
| 4 | [is] [adv] for [v-ing] | 31 |
|
