| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [v-ing] [prep] a time [Wh adv] | 12 |
|
| 2 | be [v-ing] [prep] a time when | 12 |
|
| 3 | be [v-ing] at a time [Wh adv] | 9 |
|
| 4 | be [v-ing] at a time [Wh adv] | 9 |
|
