| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be a period [prep] | 179 |
|
| 2 | [adv] a period [prep] | 117 |
|
| 3 | be [adv] a period | 27 |
|
| 4 | be [adv] a [prep] | 6 |
|
