| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [was/were] [v-ing] at | 2698 |
|
| 2 | [was/were] [v-ing] [det] | 1872 |
|
| 3 | [v-ing] at [det] | 1424 |
|
| 4 | [was/were] at [det] | 536 |
|
