SN4 ""

No	Pattern	Freq
1	it have been [vb pp] [prep] a	260
2	it has been [verb] [prep] a	144
3	it had been [verb] [prep] a	94
4	it have been [verb] as a	67
5	it have been [verb] by a	60
6	it 's been [verb] [prep] a	42
7	it have been [verb] for a	26
8	it have been [verb] in a	25
9	it have been [verb] to a	24
10	it have been [v-ing] [prep] a	22
11	it have been [verb] on a	20
12	it have been [verb] into a	20
13	it have been [verb] with a	18
14	it have been use [prep] a	15
15	it have been used [prep] a	15
16	it have been [verb] at a	9
17	it have been built [prep] a	7
18	it have been describe [prep] a	7
19	it have been build [prep] a	7
20	it have been know [prep] a	7
21	it have been described [prep] a	7
22	it have been known [prep] a	7
23	it have been go [prep] a	6
24	it have been make [prep] a	6
25	it have been going [prep] a	6
26	it have been made [prep] a	6
27	it have been hit [prep] a	5
28	it have been converted [prep] a	5
29	it have been write [prep] a	5
30	it have been hit [prep] a	5