SN4 ""

No	Pattern	Freq
1	[noun] have [been] [vb pp] for years	16
2	[noun sg] have [been] [vb pp] for years	9
3	[noun pl] have [been] [vb pp] for years	5
4	have [adv] [been] [vb pp] for years	10
5	have [not/n't] [been] [vb pp] for years	9
6	have not [been] [vb pp] for years	9
7	have not [been] [vb pp] for years	5
8	have [been] [vb pp] for [adj] years	162
9	have [been] [vb pp] for [num] years	92
10	have [been] [vb pp] for [det] years	70
11	have [been] [vb pp] for many years	50
12	have [been] [vb pp] for many years	50
13	have [been] [vb pp] for two years	15
14	have [been] [vb pp] for two years	15
15	have [been] [vb pp] for some years	15
16	have [been] [vb pp] for some years	15
17	have [been] [vb pp] for three years	14
18	have [been] [vb pp] for three years	14
19	have [been] [vb pp] for seven years	8
20	have [been] [vb pp] for seven years	8
21	have [been] [vb pp] for five years	7
22	have [been] [vb pp] for five years	7
23	have [been] [vb pp] for 12 years	5
24	have [been] [vb pp] for several years	5
25	have [been] [vb pp] for several years	5
26	have [been] [vb pp] for 12 years	5
27	have [been] [vb pp] for years [prep]	9
28	have [been] [vb pp] for years [prep]	9