| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [art] long period [modal v] | 10 |
|
| 2 | a long period [modal v] | 10 |
|
| 3 | a long period [modal v] | 10 |
|
| 4 | [art] long period [modal v] | 10 |
|
| 5 | long period [modal v] [vb infin] | 6 |
|
| 6 | long period [modal v] [verb] | 6 |
|
