| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] [v-ing] [prep] a [adv] | 230 |
|
| 2 | [v-ing] [prep] a time [adv] | 32 |
|
| 3 | [be] [prep] a time [adv] | 31 |
|
| 4 | [be] [v-ing] [prep] a time | 28 |
|
