| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a brief period [prep] | 62 |
|
| 2 | a brief period of | 33 |
|
| 3 | a brief period of | 33 |
|
| 4 | a brief period in | 11 |
|
| 5 | a brief period in | 11 |
|
| 6 | a brief period during | 7 |
|
| 7 | a brief period during | 7 |
|
