| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a brief period [prep] [art] | 13 |
|
| 2 | a brief period [prep] the | 11 |
|
| 3 | a brief period in [art] | 6 |
|
| 4 | a brief period in [art] | 6 |
|
