| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb base] for about | 127 |
|
| 2 | for about 20 | 41 |
|
| 3 | [vb base] for 20 | 27 |
|
| 4 | [vb base] about 20 | 9 |
|
