| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have [been] empty for [det] | 12 |
|
| 2 | [verb] been empty for [det] | 12 |
|
| 3 | had [been] empty for [det] | 6 |
|
| 4 | [vb past] [been] empty for [det] | 6 |
|
