SN4 ""

No	Pattern	Freq
1	it have been [prep] [adj] [noun]	50
2	it have been [prep] [adj] [noun sg]	27
3	it has been [prep] [adj] [noun]	23
4	it have been [prep] [det] [noun]	21
5	it have been [prep] [adj] [noun pl]	21
6	it have been [prep] [adj] [noun]	21
7	it had been [prep] [adj] [noun]	19
8	it have been in [adj] [noun]	11
9	it have been in [adj] [noun]	11
10	it have been for [adj] [noun]	10
11	it have been for [adj] [noun]	10
12	it have been of [adj] [noun]	10
13	it have been of [adj] [noun]	10
14	it have been [prep] [adj] years	8
15	it have been [prep] [adj] year	8
16	it 's been [prep] [adj] [noun]	7
17	it have been [prep] [num] [noun]	7
18	it have been on [adj] [noun]	6
19	it have been on [adj] [noun]	6
20	it have been with [adj] [noun]	5
21	it have been [prep] several [noun]	5
22	it have been [prep] several [noun]	5
23	it have been with [adj] [noun]	5