| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [is] [verb] at | 3808 |
|
| 2 | [is] [to-vb] at | 208 |
|
| 3 | [is] operate at | 25 |
|
| 4 | [is] to operate [prep] | 13 |
|
| 5 | [be] to operate at | 6 |
|
