SN4 ""

No	Pattern	Freq
1	[noun] which have been [prep] [noun]	9
2	[noun pl] which have been [prep] [noun]	6
3	which have been [verb] [prep] [noun]	175
4	which have been [vb pp] [prep] [noun]	167
5	which have been [v-ing] [prep] [noun]	8
6	which have been develop [prep] [noun]	7
7	which have been developed [prep] [noun]	7
8	which have been describe [prep] [noun]	7
9	which have been described [prep] [noun]	7
10	which have been used [prep] [noun]	6
11	which have been [adj] [prep] [noun]	6
12	which have been [adj] [prep] [noun]	6
13	which have been use [prep] [noun]	6
14	which have been identified [prep] [noun]	5
15	which have been identify [prep] [noun]	5
16	which have been [prep] [art] [noun]	6
17	which have been [prep] [art] [noun]	6
18	which have been [prep] [adj] [noun]	5
19	which have been [prep] [noun] [prep]	12
20	which have been [prep] [noun] [prep]	12
21	which have been [prep] [noun] since	5
22	which have been [prep] [noun] since	5