| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [vb pp] [prep] [adj] period | 150 |
|
| 2 | be [vb pp] [prep] long period | 39 |
|
| 3 | be [vb pp] [prep] longer [noun] | 21 |
|
| 4 | be [vb pp] [prep] [adj -er] period | 10 |
|
| 5 | be [vb pp] [prep] longer period | 6 |
|
| 6 | be [verb] [prep] longer period | 6 |
|
| 7 | [be] [vb pp] [prep] longer period | 6 |
|
