| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb pp] [prep] a long period | 67 |
|
| 2 | be [vb pp] [prep] a period | 61 |
|
| 3 | be [vb pp] [prep] a long | 59 |
|
| 4 | be [vb pp] [prep] long period | 15 |
|
