| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [was/were] [v-ing] a | 4665 |
|
| 2 | [was/were] [v-ing] at | 2698 |
|
| 3 | [v-ing] at a | 1472 |
|
| 4 | [was/were] at a | 386 |
|
