SN4 ""

No	Pattern	Freq
1	[be] [vb pp] three years	46
2	be [vb pp] three years	46
3	[verb] [vb pp] three years	42
4	have [vb pp] three years	41
5	[was/were] [vb pp] three years	32
6	was [vb pp] three years	25
7	[vb past] [vb pp] three years	21
8	had [vb pp] three years	17
9	[adv] [vb pp] three years	10
10	[adv] [vb pp] three years	10
11	[vb base] [vb pp] three years	9
12	were [vb pp] three years	7
13	[vb -s] [vb pp] three years	7
14	've [vb pp] three years	6
15	has [vb pp] three years	5
16	[vb pp] [prep] three years	166
17	[vb pp] [prep] three years	166
18	[vb pp] for three years	99
19	[vb pp] for three years	99
20	[vb pp] [adv] three years	50
21	[vb pp] [adv] three years	39
22	[vb pp] over three years	28
23	[vb pp] over three years	25
24	[vb pp] to three years	24
25	[vb pp] to three years	24
26	[vb pp] [art] three years	18
27	[vb pp] every three years	18
28	[vb pp] [art] three years	18
29	[vb pp] every three years	18
30	[vb pp] within three years	15