SN4 ""

No	Pattern	Freq
1	have been [vb pp] [prep] [adj] years	73
2	have been [verb] for [adj] years	48
3	have been [verb] [prep] [adj] years	38
4	have been [verb] in [adj] years	38
5	have been [verb] [prep] recent years	35
6	have been [verb] [prep] recent years	35
7	have been [verb] [prep] [det] years	28
8	have been [verb] [prep] [num] years	28
9	have been [v-ing] [prep] [adj] years	21
10	have been [verb] [prep] many years	20
11	have been [verb] [prep] many years	20
12	have been [verb] [prep] two years	8
13	have been [verb] [prep] two years	8
14	have been know [prep] [adj] years	7
15	have been known [prep] [adj] years	7
16	have been [verb] over [adj] years	7
17	have been [verb] [prep] several years	5
18	have been made [prep] [adj] years	5
19	have been make [prep] [adj] years	5
20	have been develop [prep] [adj] years	5
21	have been [verb] [prep] several years	5