| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] what [is] | 3575 |
|
| 2 | what [is] [v-ing] | 3281 |
|
| 3 | [verb] [is] [v-ing] | 621 |
|
| 4 | [verb] what [v-ing] | 18 |
|
