SN4 ""

No	Pattern	Freq
1	it is [adj] for [det]	176
2	it is [adj] for [det]	167
3	it is [adv] for [det]	23
4	it is [verb] for [det]	18
5	it is possible for [det]	17
6	it is [adv] for [det]	17
7	it is possible for [det]	17
8	it is [vb pp] for [det]	13
9	it is difficult for [det]	12
10	it is difficult for [det]	12
11	it is important for [det]	9
12	it is impossible for [det]	9
13	it is important for [det]	9
14	it is impossible for [det]	9
15	it is hard for [det]	8
16	it is necessary for [det]	8
17	it is necessary for [det]	8
18	it is [noun] for [det]	8
19	it is hard for [det]	8
20	it is [noun sg] for [det]	8
21	it is rare for [det]	7
22	it is rare for [det]	7
23	it is good for [det]	7
24	it is common for [det]	6
25	it is suitable for [det]	6
26	it is essential for [det]	6
27	it is easy for [det]	6
28	it is perhaps for [det]	6
29	it is usual for [det]	6
30	it is suitable for [det]	6