| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a long period [modal v] | 6 |
|
| 2 | [prep] a long period [modal v] | 6 |
|
| 3 | [prep] [art] long period [modal v] | 6 |
|
| 4 | [prep] [art] long period [vb mod] | 6 |
|
| 5 | over [art] long period [modal v] | 5 |
|
