| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over 20 years ' [noun sg] | 5 |
|
| 2 | over 20 years ' [noun sg] | 5 |
|
| 3 | over 20 years ' [noun sg] | 5 |
|
| 4 | over 20 years ' experience | 5 |
|
