| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] it [is] [v-ing] | 732 |
|
| 2 | [vb -s] [pron] [is] [v-ing] | 599 |
|
| 3 | [vb -s] it [is] [verb] | 286 |
|
| 4 | [vb -s] it [be] [v-ing] | 219 |
|
