SN4 ""

No	Pattern	Freq
1	it have been [adj] [prep]	263
2	it has been [adj] [prep]	126
3	it have been [adj] for	115
4	it have been [adj] for	115
5	it had been [adj] [prep]	93
6	it 's been [adj] [prep]	40
7	it have been [adj] in	40
8	it have been [adj] in	40
9	it have been [adj] to	38
10	it have been [adj] to	38
11	it have been possible [prep]	17
12	it have been [adj] of	13
13	it have been [adj] from	13
14	it have been necessary [prep]	13
15	it have been [adj] from	13
16	it have been [adj] of	13
17	it have been clear [prep]	11
18	it have been [adj] on	9
19	it have been [adj] on	9
20	it have been [adj] at	7
21	it have been [adj] since	7
22	it have been [adj] since	7
23	it have been good [prep]	7
24	it have been open [prep]	7
25	it have been [adj] at	7
26	it have been [adj] with	6
27	it have been responsible [prep]	6
28	it have been [adj] with	6
29	it have been obvious [prep]	5
30	it have been difficult [prep]	5