| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had been [prep] [art] | 1396 |
|
| 2 | been operate [prep] [art] | 20 |
|
| 3 | had operate [prep] [art] | 19 |
|
| 4 | had been operate [prep] | 13 |
|
