| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could be [vb pp] [prep] a [noun] | 529 |
|
| 2 | could be [vb pp] [prep] a [noun sg] | 499 |
|
| 3 | [vb mod] be [vb pp] [prep] a period | 31 |
|
| 4 | [modal v] be [vb pp] [prep] a period | 31 |
|
| 5 | could be [vb pp] [prep] [art] period | 7 |
|
| 6 | could be [vb pp] [prep] [art] period | 7 |
|
| 7 | could be [vb pp] [prep] a period | 6 |
|
| 8 | could [be] [vb pp] [prep] a period | 6 |
|
| 9 | could be [vb pp] [prep] a period | 6 |
|
| 10 | could be [vb pp] [prep] a period | 6 |
|
| 11 | could be [vb pp] [prep] a period | 6 |
|
| 12 | could [be] [vb pp] [prep] a period | 6 |
|
| 13 | could be [verb] [prep] a period | 6 |
|
| 14 | could be [vb pp] [prep] a period | 6 |
|
