| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] been operate for | 15 |
|
| 2 | [verb] be operating for | 15 |
|
| 3 | [verb] be operate for | 15 |
|
| 4 | have be operate for | 15 |
|
| 5 | [vb -s] be operate for | 13 |
|
| 6 | has be operate for | 13 |
|
