SN4 ""

No	Pattern	Freq
1	it [be] [adv] [adj] [to-vb] and	83
2	it be [adv] [adj] [to-vb] and	83
3	it [be] [adv] [adj] [to-vb] and	73
4	it [is] [adv] [adj] [to-vb] and	61
5	it is [adv] [adj] [to-vb] and	40
6	it [was/were] [adv] [adj] [to-vb] and	22
7	it was [adv] [adj] [to-vb] and	21
8	it 's [adv] [adj] [to-vb] and	21
9	it [be] very [adj] [to-vb] and	14
10	it [be] [adv] easy [to-vb] and	14
11	it [be] [adv] [adj] to try and	13
12	it [be] too [adj] [to-vb] and	11
13	it [be] [adv] easy [to-vb] and	10
14	it [be] [adv] [adj -er] [to-vb] and	9
15	it [be] [adv] difficult [to-vb] and	8
16	it [be] [adv] difficult [to-vb] and	8
17	it [be] so [adj] [to-vb] and	7
18	it [be] [adv] late [to-vb] and	6
19	it [be] [adv] important [to-vb] and	6
20	it [be] [adv] important [to-vb] and	6
21	it [be] [adv] late [to-vb] and	6