| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | has [be] operating for [num] | 5 |
|
| 2 | [vb -s] [be] operating for [num] | 5 |
|
| 3 | [vb -s] be operating for [num] | 5 |
|
| 4 | [vb -s] been operating for [num] | 5 |
|
| 5 | [vb -s] [been] operating for [num] | 5 |
|
