| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [adj] period [prep] | 1333 |
|
| 2 | a [adj] period [prep] | 1253 |
|
| 3 | a [adj] period [prep] | 1182 |
|
| 4 | a [adj] period of | 954 |
|
| 5 | a long period [prep] | 245 |
|
| 6 | a long period [prep] | 216 |
|
| 7 | an [adj] period [prep] | 151 |
|
| 8 | a short period [prep] | 133 |
|
| 9 | a [adj] period in | 130 |
|
| 10 | a short period [prep] | 126 |
|
| 11 | a [adj -er] period [prep] | 73 |
|
| 12 | a brief period [prep] | 63 |
|
| 13 | a brief period [prep] | 62 |
|
| 14 | a [adj] period for | 51 |
|
| 15 | a fixed period [prep] | 33 |
|
| 16 | a fixed period [prep] | 33 |
|
| 17 | a prolonged period [prep] | 32 |
|
| 18 | a prolonged period [prep] | 32 |
|
| 19 | a limited period [prep] | 30 |
|
| 20 | a limited period [prep] | 30 |
|
| 21 | a longer period [prep] | 29 |
|
| 22 | a certain period [prep] | 26 |
|
| 23 | a certain period [prep] | 26 |
|
| 24 | a considerable period [prep] | 26 |
|
| 25 | a considerable period [prep] | 26 |
|
| 26 | a [adj] period during | 25 |
|
| 27 | a reasonable period [prep] | 24 |
|
| 28 | a [adj] period after | 24 |
|
| 29 | a reasonable period [prep] | 24 |
|
| 30 | a lengthy period [prep] | 23 |
|
