SN4 ""

No	Pattern	Freq
1	over a [adv] long period	21
2	over a [adv] long period	21
3	over a much long period	9
4	over a much long period	9
5	[noun] over a long period	120
6	[noun sg] over a long period	81
7	[verb] over a long period	46
8	[vb pp] over a long period	44
9	[noun pl] over a long period	34
10	[adv] over a long period	22
11	[adv] over a long period	17
12	[conj] over a long period	11
13	[coord] over a long period	8
14	[adj] over a long period	6
15	[adv prt] over a long period	5
16	over [det] a long period	5
17	over such a long period	5
18	over such a long period	5
19	over [adj] a long period	5
20	over a long period [prep]	93
21	over a long period [prep]	93
22	over a long period of	84
23	over a long period of	84
24	over a long period [conj]	16
25	over a long period [coord]	12
26	over a long period and	11
27	over a long period and	11
28	over a long period [vb mod]	5
29	over a long period [modal v]	5
30	over a long period [verb]	5