| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a period of [adv] | 40 |
|
| 2 | [prep] a period of about | 29 |
|
| 3 | [prep] a period of about | 29 |
|
| 4 | over a [noun sg] of about | 17 |
|
| 5 | over a [noun] of about | 17 |
|
| 6 | over [art] period of about | 15 |
|
| 7 | over [art] period of about | 15 |
|
| 8 | over a period of about | 14 |
|
| 9 | over a period of about | 14 |
|
| 10 | over a period of about | 14 |
|
| 11 | over a period of about | 14 |
|
| 12 | over a period [prep] about | 14 |
|
| 13 | over a period [prep] about | 14 |
|
