SN4 ""

No	Pattern	Freq
1	[conj] it have been [noun] [noun]	10
2	[noun] it have been [noun] [noun]	7
3	[subord] it have been [noun] [noun]	5
4	[noun pl] it have been [noun] [noun]	5
5	year it have been [noun] [noun]	5
6	if it have been [noun] [noun]	5
7	if it have been [noun] [noun]	5
8	it [vb mod] have been [noun] [noun]	27
9	it [modal v] have been [noun] [noun]	27
10	it could have been [noun] [noun]	10
11	it could have been [noun] [noun]	10
12	it must have been [noun] [noun]	8
13	it must have been [noun] [noun]	8
14	it have [adv] been [noun] [noun]	5
15	it have been [art] [noun] [noun]	49
16	it have been [art] [noun] [noun]	49
17	it have been a [noun] [noun]	37
18	it have been a [noun] [noun]	35
19	it have been the [noun] [noun]	12
20	it have been [verb] [noun] [noun]	12
21	it have been the [noun] [noun]	12
22	it have been [prep] [noun] [noun]	8
23	it have been [prep] [noun] [noun]	8
24	it have been [vb pp] [noun] [noun]	6
25	it have been [v-ing] [noun] [noun]	5
26	it have been [noun] [unc] [noun]	17
27	it have been [noun] ['s] [noun]	17
28	it have been [noun] 's [noun]	16
29	it have been [noun] 's [noun]	16
30	it have been [noun] [coord] [noun]	10