SN4 ""

No	Pattern	Freq
1	it have not been [adj]	162
2	it have not been [adj]	142
3	it have not been [adj]	111
4	it has not been [adj]	103
5	it have n't been [adj]	51
6	it had not been [adj]	48
7	it have not been possible	46
8	it have not been possible	46
9	it have not been easy	33
10	it have not been easy	33
11	it have not been [det]	16
12	it have not been able	10
13	it have not been able	10
14	it 's not been [adj]	10
15	it have not been necessary	8
16	it have not been necessary	8
17	it have not been such	5
18	it have not been much	5
19	it have not been much	5
20	it have not been such	5