| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a period | 2137 |
|
| 2 | [prep] a period | 2137 |
|
| 3 | over a period | 681 |
|
| 4 | over a period | 681 |
|
| 5 | for a period | 517 |
|
| 6 | for a period | 517 |
|
| 7 | [verb] a period | 408 |
|
| 8 | be a period | 232 |
|
| 9 | [be] a period | 232 |
|
| 10 | in a period | 180 |
|
| 11 | in a period | 180 |
|
| 12 | after a period | 175 |
|
| 13 | after a period | 175 |
|
| 14 | [adv] a period | 152 |
|
| 15 | [was/were] a period | 123 |
|
| 16 | during a period | 110 |
|
| 17 | during a period | 110 |
|
| 18 | was a period | 108 |
|
| 19 | [conj] a period | 101 |
|
| 20 | [vb past] a period | 88 |
|
| 21 | [v-ing] a period | 75 |
|
| 22 | [adv prt] a period | 74 |
|
| 23 | of a period | 74 |
|
| 24 | of a period | 74 |
|
| 25 | [adv] a period | 69 |
|
| 26 | over a period | 67 |
|
| 27 | over a period | 67 |
|
| 28 | to a period | 63 |
|
| 29 | [vb -s] a period | 63 |
|
| 30 | to a period | 63 |
|
