No | Pattern | Freq | Relations |
---|---|---|---|
1 | be [vb pp] [prep] a period of | 50 | |
2 | be [vb pp] over a period [prep] | 15 | |
3 | be [vb pp] for a period [prep] | 13 | |
4 | be [vb pp] within a period [prep] | 10 | |
5 | be [vb pp] by a period [prep] | 5 | |
6 | be [vb pp] as a period [prep] | 5 |