| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [vb pp] [prep] a [adj] period | 55 |
|
| 2 | be [vb pp] for a [adj] period | 27 |
|
| 3 | be [vb pp] over a [adj] period | 21 |
|
| 4 | be [vb pp] [prep] a [adj -er] period | 15 |
|
| 5 | be [vb pp] [prep] a long period | 14 |
|
| 6 | be [vb pp] [prep] a short period | 12 |
|
| 7 | be [vb pp] [prep] a longer period | 10 |
|
| 8 | be [vb pp] [prep] a short period | 8 |
|
| 9 | be [vb pp] within a [adj] period | 8 |
|
| 10 | be [vb pp] [prep] a limited period | 6 |
|
| 11 | be [vb pp] [prep] a limited period | 6 |
|
| 12 | be [vb pp] in a [adj] period | 5 |
|
