| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [vb pp] for a [adj] period | 23 |
|
| 2 | be [vb pp] over a [adj] period | 11 |
|
| 3 | be [vb pp] [prep] a short period | 8 |
|
| 4 | be [vb pp] within a [adj] period | 8 |
|
| 5 | be [vb pp] [prep] a limited period | 6 |
|
| 6 | be [vb pp] in a [adj] period | 5 |
|
