| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] been placed at | 5 |
|
| 2 | had [be] placed at | 5 |
|
| 3 | [vb past] [been] placed at | 5 |
|
| 4 | [vb past] be placed at | 5 |
|
