SN4 ""

No	Pattern	Freq
1	it [adj] [verb] the [noun]	492
2	it [adj] [to-vb] the [noun]	467
3	it [adj] [verb] the [noun]	422
4	it [adj] [verb] the [noun sg]	366
5	it difficult [verb] the [noun]	108
6	it [adj] [verb] the [noun pl]	108
7	it difficult [verb] the [noun]	108
8	it possible [verb] the [noun]	78
9	it possible [verb] the [noun]	78
10	it easy [verb] the [noun]	56
11	it necessary [verb] the [noun]	50
12	it necessary [verb] the [noun]	50
13	it [adj -er] [verb] the [noun]	47
14	it hard [verb] the [noun]	40
15	it easier [verb] the [noun]	35
16	it hard [verb] the [noun]	34
17	it impossible [verb] the [noun]	33
18	it impossible [verb] the [noun]	33
19	it easy [verb] the [noun]	19
20	it [adj] [verb] the [noun prp]	12
21	it [adj] to see the [noun]	11
22	it [adj] see the [noun]	11
23	it [num ord] [verb] the [noun]	9
24	it [adj] [vb -s] the [noun]	9
25	it [adj] keep the [noun]	9
26	it [det] [verb] the [noun]	9
27	it [adj] determine the [noun]	8
28	it [adj] to use the [noun]	8
29	it [adj] to keep the [noun]	8
30	it [adj] to determine the [noun]	8