| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | has [been] [v-ing] a | 169 |
|
| 2 | has [been] [v-ing] at | 73 |
|
| 3 | [been] [v-ing] at a | 47 |
|
| 4 | has [been] at a | 8 |
|
