| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [been] [v-ing] for 20 years | 5 |
|
| 2 | been [v-ing] for 20 years | 5 |
|
| 3 | [be] [v-ing] for 20 years | 5 |
|
| 4 | be [v-ing] for 20 years | 5 |
|
