| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [v-ing] [prep] a [noun] [prep] [noun sg] | 1156 |
|
| 2 | [verb] [prep] a period [prep] [noun sg] | 121 |
|
| 3 | [v-ing] [prep] [art] period [prep] [noun sg] | 22 |
|
| 4 | [v-ing] [prep] a period [prep] [noun] | 13 |
|
