| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [vb pp] for [art] [adj] period | 8 |
|
| 2 | [is] [vb pp] for [art] [adj] period | 7 |
|
| 3 | [is] [vb pp] for a [adj] period | 6 |
|
