| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been operating [prep] | 50 |
|
| 2 | has been operating [prep] | 24 |
|
| 3 | have been operating in | 16 |
|
| 4 | have been operating in | 16 |
|
| 5 | have been operating for | 15 |
|
| 6 | have been operating for | 15 |
|
| 7 | have been operating [prep] | 12 |
|
| 8 | had been operating [prep] | 8 |
|
| 9 | have been operating since | 6 |
|
| 10 | have been operating since | 6 |
|
