| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [prep] four years ' | 18 |
|
| 2 | be [prep] four years ['s] | 18 |
|
| 3 | be [prep] four years ' | 18 |
|
| 4 | be of four years [unc] | 17 |
|
| 5 | is [prep] four years [unc] | 15 |
|
