| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [art] [adj] period of | 950 |
|
| 2 | [art] [adj] period of time | 387 |
|
| 3 | [prep] [art] period of time | 257 |
|
| 4 | [prep] [adj] period of time | 176 |
|
