| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [det] than [det] a century | 25 |
|
| 2 | [det] than half a century | 25 |
|
| 3 | [det] than half a century | 25 |
|
| 4 | [det] than [adj] a century | 25 |
|
| 5 | more than [adj] a century | 22 |
|
