SN4 ""

No	Pattern	Freq
1	it is [adj] for [noun pl]	243
2	it is [adj] for [noun pl]	239
3	it is important for [noun pl]	34
4	it is important for [noun pl]	34
5	it is possible for [noun pl]	30
6	it is possible for [noun pl]	30
7	it is common for [noun pl]	21
8	it is common for [noun pl]	21
9	it is difficult for [noun pl]	20
10	it is difficult for [noun pl]	20
11	it is [verb] for [noun pl]	17
12	it is [vb pp] for [noun pl]	10
13	it is usual for [noun pl]	10
14	it is usual for [noun pl]	10
15	it is [adv] for [noun pl]	9
16	it is good for [noun pl]	8
17	it is [adv] for [noun pl]	7
18	it is essential for [noun pl]	7
19	it is [v-ing] for [noun pl]	7
20	it is essential for [noun pl]	7
21	it is customary for [noun pl]	6
22	it is easy for [noun pl]	6
23	it is customary for [noun pl]	6
24	it is good for [noun pl]	6
25	it is appropriate for [noun pl]	5
26	it is impossible for [noun pl]	5
27	it is easy for [noun pl]	5
28	it is appropriate for [noun pl]	5
29	it is impossible for [noun pl]	5
30	[adj] it is for [noun pl]	18