| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [vb pp] [prep] a [adj] period | 162 |
|
| 2 | be [vb pp] [prep] a long period | 34 |
|
| 3 | be [vb pp] [prep] a longer [noun] | 21 |
|
| 4 | be [vb pp] [prep] a [adj -er] period | 18 |
|
| 5 | be [vb pp] [prep] a longer period | 11 |
|
| 6 | be [vb pp] [prep] [art] longer period | 11 |
|
| 7 | be [verb] [prep] a longer period | 11 |
|
| 8 | be [vb pp] [prep] [art] longer period | 11 |
|
| 9 | [be] [vb pp] [prep] a longer period | 11 |
|
| 10 | be [vb pp] [prep] a longer period | 11 |
|
