| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] [been] [v-ing] at [det] | 8 |
|
| 2 | [vb past] been [v-ing] at [det] | 8 |
|
| 3 | had [been] [v-ing] at [det] | 7 |
|
