| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it is [v-ing] | 2521 |
|
| 2 | it is [be] | 469 |
|
| 3 | is [v-ing] [be] | 227 |
|
| 4 | it [v-ing] [be] | 20 |
|
