SN4 ""

No	Pattern	Freq
1	[vb mod] have [been] seen	39
2	[modal v] have [been] seen	39
3	would have [been] seen	12
4	would have [been] seen	12
5	[adv] have [been] seen	10
6	may have [been] seen	8
7	might have [been] seen	8
8	might have [been] seen	8
9	may have [been] seen	8
10	[not/n't] have [been] seen	6
11	not have [been] seen	6
12	could have [been] seen	5
13	could have [been] seen	5
14	have [been] seen [prep]	28
15	have [been] seen [prep]	28
16	have [been] seen as	15
17	have [been] seen as	15
18	have [been] seen [conj]	10
19	have [been] seen [subord]	9
20	have [been] seen as	8
21	have [been] seen as	8
22	have [been] seen in	5
23	have [been] seen in	5