| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a brief period [prep] [adj] | 10 |
|
| 2 | a brief period of [adj] | 8 |
|
| 3 | a brief period of [adj] | 8 |
|
| 4 | a brief period [prep] [adj] | 7 |
|
