SN4 ""

No	Pattern	Freq
1	over a [adj] period [prep] [noun]	141
2	over a [adj] period [prep] [noun]	141
3	over a [adj] period [prep] [noun]	134
4	over a [adj] period [prep] [noun sg]	129
5	over a [adj] period of [noun]	126
6	over a [adj] period of [noun]	126
7	over a [adj] period [prep] time	120
8	over a [adj] period [prep] time	120
9	over a long period [prep] [noun]	84
10	over a long period [prep] [noun]	78
11	over a short period [prep] [noun]	8
12	over a considerable period [prep] [noun]	7
13	over a short period [prep] [noun]	7
14	over a prolonged period [prep] [noun]	7
15	over a [adj -er] period [prep] [noun]	7
16	over a prolonged period [prep] [noun]	7
17	over a considerable period [prep] [noun]	7
18	over a given period [prep] [noun]	6
19	over a [adj] period [prep] [noun prp]	6
20	over a longer period [prep] [noun]	6
21	over a given period [prep] [noun]	6
22	over a [adj] period [prep] year	5
23	over a [adj] period [prep] [noun pl]	5
24	over a [adj] period [prep] years	5