| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [vb pp] [prep] a [adj] period | 176 |
|
| 2 | be [vb pp] [prep] a long [noun] | 167 |
|
| 3 | be [vb pp] [prep] a long [noun sg] | 164 |
|
| 4 | be [verb] [prep] a long period | 37 |
|
| 5 | be [vb pp] [prep] [art] long period | 35 |
|
| 6 | [be] [vb pp] [prep] a long period | 34 |
|
| 7 | be [vb pp] [prep] a long period | 34 |
|
