SN4 ""

No	Pattern	Freq
1	[conj] it have been [det] [noun]	17
2	[coord] it have been [det] [noun]	8
3	[subord] it have been [det] [noun]	8
4	and it have been [det] [noun]	7
5	and it have been [det] [noun]	7
6	it [modal v] have been [det] [noun]	41
7	it [vb mod] have been [det] [noun]	41
8	it must have been [det] [noun]	19
9	it must have been [det] [noun]	19
10	it could have been [det] [noun]	7
11	it could have been [det] [noun]	7
12	it might have been [det] [noun]	6
13	it might have been [det] [noun]	6
14	it may have been [det] [noun]	5
15	it may have been [det] [noun]	5
16	it have [adv] been [det] [noun]	9
17	it have [adv] been [det] [noun]	7
18	it have been [verb] [det] [noun]	78
19	it have been [vb pp] [det] [noun]	64
20	it have been [prep] [det] [noun]	21
21	it have been [prep] [det] [noun]	21
22	it have been [v-ing] [det] [noun]	13
23	it have been [adj] [det] [noun]	9
24	it have been suggested [det] [noun]	9
25	it have been suggest [det] [noun]	9
26	it have been [adj] [det] [noun]	5
27	it have been [pron] [det] [noun]	5
28	it have been on [det] [noun]	5
29	it have been reported [det] [noun]	5
30	it have been on [det] [noun]	5