| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [subord] it [is] [adv] [verb] | 1209 |
|
| 2 | [conj] it [is] [adv] [v-ing] | 534 |
|
| 3 | [subord] [pron] [is] [adv] [v-ing] | 461 |
|
| 4 | [subord] it [be] [adv] [v-ing] | 251 |
|
