| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] has be operating [prep] | 12 |
|
| 2 | [noun] [vb -s] been operating [prep] | 12 |
|
| 3 | [noun sg] [vb -s] be operating [prep] | 10 |
|
| 4 | [noun] [vb -s] be operating for | 6 |
|
