| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be of [num] years ' | 48 |
|
| 2 | be of [num] years ' | 48 |
|
| 3 | be of [num] years ['s] | 48 |
|
| 4 | is of [num] years [unc] | 44 |
|
| 5 | be of three years [unc] | 24 |
|
| 6 | be of four years [unc] | 17 |
|
| 7 | be of two years [unc] | 7 |
|
