SN4 ""

No	Pattern	Freq
1	[verb] [adv] difficult it [be]	58
2	the [adv] difficult it [be]	19
3	the [adv] difficult it [be]	19
4	[art] [adv] difficult it [be]	19
5	[art] [adv] difficult it [be]	19
6	[adv] [adv] difficult it [be]	16
7	[vb base] [adv] difficult it [be]	15
8	[vb past] [adv] difficult it [be]	14
9	[prep] [adv] difficult it [be]	14
10	[prep] [adv] difficult it [be]	14
11	know [adv] difficult it [be]	12
12	know [adv] difficult it [be]	9
13	[adv] [adv] difficult it [be]	8
14	[to-vb] [adv] difficult it [be]	8
15	[conj] [adv] difficult it [be]	7
16	[coord] [adv] difficult it [be]	7
17	and [adv] difficult it [be]	7
18	and [adv] difficult it [be]	7
19	[v-ing] [adv] difficult it [be]	6
20	about [adv] difficult it [be]	6
21	about [adv] difficult it [be]	6
22	[adj] [adv] difficult it [be]	6
23	[adj] [adv] difficult it [be]	6
24	[vb -s] [adv] difficult it [be]	6
25	[pron] [adv] difficult it [be]	5
26	[Wh adv] [adv] difficult it [be]	5
27	of [adv] difficult it [be]	5
28	of [adv] difficult it [be]	5
29	[vb pp] [adv] difficult it [be]	5
30	how [adv] difficult it [be]	5