| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] be [vb pp] [prep] a period | 31 |
|
| 2 | [modal v] be [vb pp] for a period | 10 |
|
| 3 | [modal v] be [vb pp] over a period | 7 |
|
| 4 | could be [vb pp] [prep] a period | 6 |
|
| 5 | could be [vb pp] [prep] a period | 6 |
|
| 6 | can be [vb pp] [prep] a period | 5 |
|
| 7 | can be [vb pp] [prep] a period | 5 |
|
| 8 | [modal v] be [vb pp] as a period | 5 |
|
