SN4 ""

No	Pattern	Freq
1	it have been [verb] that [adj]	115
2	it have [been] [verb] that [adj]	115
3	it have [been] [vb pp] that [adj]	115
4	it have [been] [verb] that [adj]	115
5	it has [been] [verb] that [adj]	105
6	it have [been] suggested that [adj]	22
7	it have [been] suggest that [adj]	22
8	it have [been] argue that [adj]	13
9	it have [been] shown that [adj]	13
10	it have [been] argued that [adj]	13
11	it have [been] show that [adj]	13
12	it had [been] [verb] that [adj]	8
13	it have [been] claimed that [adj]	8
14	it have [been] estimate that [adj]	8
15	it have [been] claim that [adj]	8
16	it have [been] estimated that [adj]	8
17	it have [been] find that [adj]	6
18	it have [been] report that [adj]	6
19	it have [been] reported that [adj]	6
20	it have [been] found that [adj]	6
21	it have [been] established that [adj]	5
22	it have [been] assume that [adj]	5
23	it have [been] establish that [adj]	5
24	it have [been] assumed that [adj]	5