| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb pp] for a period | 54 |
|
| 2 | [vb infin] for a period | 13 |
|
| 3 | [v-ing] for a period | 11 |
|
| 4 | [vb past] for a period | 10 |
|
| 5 | [to-vb] for a period | 8 |
|
| 6 | continue for a period | 6 |
|
| 7 | [vb -s] for a period | 6 |
|
| 8 | work for a period | 5 |
|
