| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [v-ing] [prep] | 40005 |
|
| 2 | [v-ing] [prep] an | 4147 |
|
| 3 | [prep] [v-ing] an | 3592 |
|
| 4 | [prep] [prep] an | 333 |
|
