| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | been [verb] since | 567 |
|
| 2 | been [v-ing] since | 154 |
|
| 3 | been operating [prep] | 60 |
|
| 4 | been operating [prep] | 60 |
|
| 5 | been operate since | 7 |
|
| 6 | been operating since | 7 |
|
| 7 | [be] operating since | 7 |
|
| 8 | [been] operating since | 7 |
|
| 9 | be operating since | 7 |
|
