| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [is] [prep] | 14642 |
|
| 2 | it [is] [v-ing] | 7295 |
|
| 3 | [is] [prep] [v-ing] | 3232 |
|
| 4 | it [prep] [v-ing] | 1118 |
|
