SN4 ""

No	Pattern	Freq
1	[conj] it have been [adv] [prep]	36
2	[subord] it have been [adv] [prep]	23
3	[noun] it have been [adv] [prep]	10
4	if it have been [adv] [prep]	8
5	if it have been [adv] [prep]	8
6	[noun sg] it have been [adv] [prep]	8
7	[coord] it have been [adv] [prep]	8
8	[verb] it have been [adv] [prep]	6
9	and it have been [adv] [prep]	5
10	as it have been [adv] [prep]	5
11	that it have been [adv] [prep]	5
12	and it have been [adv] [prep]	5
13	[that] it have been [adv] [prep]	5
14	as it have been [adv] [prep]	5
15	that it have been [adv] [prep]	5
16	it [vb mod] have been [adv] [prep]	34
17	it [modal v] have been [adv] [prep]	34
18	it would have been [adv] [prep]	18
19	it would have been [adv] [prep]	18
20	it must have been [adv] [prep]	8
21	it must have been [adv] [prep]	8
22	it have [adv] been [adv] [prep]	24
23	it have [not/n't] been [adv] [prep]	12
24	it have [adv] been [adv] [prep]	12
25	it have not been [adv] [prep]	12
26	it have n't been [adv] [prep]	8
27	it have been [verb] [adv] [prep]	286
28	it have been [vb pp] [adv] [prep]	235
29	it have been [v-ing] [adv] [prep]	50
30	it have been go [adv] [prep]	21