| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [v-ing] [prep] an | 4148 |
|
| 2 | [v-ing] back [prep] | 3877 |
|
| 3 | back [prep] an | 228 |
|
| 4 | [v-ing] back an | 8 |
|
