| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] [noun] [prep] time | 540 |
|
| 2 | [prep] a [adj] period [prep] [noun] | 488 |
|
| 3 | [prep] a [adj] period [prep] [noun sg] | 442 |
|
| 4 | [prep] [art] [adj] period [prep] time | 321 |
|
| 5 | [prep] a [adj] period [prep] time | 297 |
|
| 6 | [prep] a [adj] period [prep] time | 297 |
|
