| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | at [adv] [prep] the [num ord] century | 19 |
|
| 2 | at least [prep] [art] [num ord] century | 19 |
|
| 3 | at [adv] [prep] the [num ord] century | 19 |
|
| 4 | at [adv] [prep] [art] [num ord] century | 19 |
|
| 5 | at least [prep] [art] [num ord] century | 19 |
|
| 6 | at [adv] [prep] [art] [num ord] century | 19 |
|
| 7 | at [adv] in [art] [num ord] century | 7 |
|
| 8 | at [adv] since [art] [num ord] century | 5 |
|
