| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] a short period [prep] | 11 |
|
| 2 | [verb] a short period [prep] | 10 |
|
| 3 | [verb] a short period of | 8 |
|
| 4 | [vb base] a short period [prep] | 6 |
|
