SN4 ""

No	Pattern	Freq
1	it have been [vb pp] [prep] [det]	135
2	it has been [vb pp] [prep] [det]	91
3	it have been [vb pp] [prep] some	43
4	it have been [vb pp] by [det]	32
5	it have been [vb pp] by [det]	32
6	it had been [vb pp] [prep] [det]	30
7	it have been [vb pp] for [det]	29
8	it have been [vb pp] for [det]	29
9	it have been [vb pp] in [det]	20
10	it have been [vb pp] in [det]	20
11	it have been [vb pp] [prep] many	20
12	it have been known [prep] [det]	14
13	it have been [vb pp] [prep] that	13
14	it have been [vb pp] [prep] this	12
15	it have been [vb pp] at [det]	11
16	it have been [vb pp] at [det]	11
17	it 's been [vb pp] [prep] [det]	10
18	it have been [vb pp] [prep] all	10
19	it have been used [prep] [det]	10
20	it have been [vb pp] [prep] several	10
21	it have been [vb pp] on [det]	8
22	it have been suggested [prep] [det]	8
23	it have been [vb pp] on [det]	8
24	it have been [vb pp] from [det]	7
25	it have been [vb pp] from [det]	7
26	it have been [vb pp] [prep] both	6
27	it have been [vb pp] to [det]	6
28	it have been [vb pp] to [det]	6
29	it have been argued [prep] [det]	5
30	it have been [vb pp] above [det]	5