| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been built up [prep] the | 18 |
|
| 2 | had been built up [prep] the | 10 |
|
| 3 | has been built up [prep] the | 7 |
|
| 4 | have been built up over the | 5 |
|
