| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [was/were] introduce [prep] the [num ord] century | 7 |
|
| 2 | [was/were] introduce [prep] the [num ord] century | 7 |
|
| 3 | [was/were] introduced [prep] the [num ord] century | 7 |
|
| 4 | [was/were] introduce in the [num ord] century | 6 |
|
| 5 | [was/were] introduce in the [num ord] century | 6 |
|
