| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | four years [unc] | 80 |
|
| 2 | four years ' | 74 |
|
| 3 | four years ['s] | 74 |
|
| 4 | four years ' | 74 |
|
| 5 | four years [no cls] | 6 |
|
