| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [v-ing] [prep] a | 31510 |
|
| 2 | been [v-ing] [prep] | 6841 |
|
| 3 | been [prep] a | 1221 |
|
| 4 | been [v-ing] a | 1008 |
|
