| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [det] than half a century | 15 |
|
| 2 | [prep] [det] than half a century | 15 |
|
| 3 | for [det] than half a century | 12 |
|
| 4 | for [det] than half a century | 12 |
|
| 5 | [det] than half a century [adv] | 6 |
|
| 6 | [det] than half a century [adv] | 6 |
|
