| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [subord] it [is] [verb] | 4795 |
|
| 2 | [subord] [pron] [is] [v-ing] | 2359 |
|
| 3 | [conj] it [is] [v-ing] | 1906 |
|
| 4 | [subord] it [be] [v-ing] | 1292 |
|
