| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun sg] has been [v-ing] [prep] a | 30 |
|
| 2 | [noun sg] [vb -s] been [v-ing] for a | 11 |
|
| 3 | [noun sg] [vb -s] been [v-ing] at a | 8 |
|
