SN4 ""

No	Pattern	Freq
1	it to have been [verb]	7
2	it to have been [vb pp]	7
3	it to have been [art]	6
4	it to have been [art]	6
5	it to have been [adj]	5
6	[verb] it to have been	20
7	it [verb] to have been	118
8	it [vb -s] to have been	101
9	it seem to have been	79
10	it seems to have been	74
11	it appear to have been	25
12	it appears to have been	19
13	it [vb past] to have been	16
14	it ought to have been	8
15	it [modal v] to have been	8
16	it [vb mod] to have been	8
17	it ought to have been	8
18	it was to have been	7
19	it [was/were] to have been	7
20	it be to have been	7
21	it [be] to have been	7
22	it appeared to have been	6
23	it have to have been	5
24	it seemed to have been	5