SN4 ""

No	Pattern	Freq
1	[conj] it is difficult	483
2	[coord] it is difficult	209
3	[subord] it is difficult	147
4	[noun] it is difficult	133
5	that it is difficult	127
6	that it is difficult	127
7	[that] it is difficult	127
8	and it is difficult	114
9	and it is difficult	114
10	but it is difficult	95
11	but it is difficult	95
12	[noun sg] it is difficult	91
13	[adv] it is difficult	75
14	[adv] it is difficult	59
15	[noun pl] it is difficult	36
16	although it is difficult	34
17	although it is difficult	34
18	[pron] it is difficult	28
19	[Wh det] it is difficult	27
20	which it is difficult	26
21	[adj] it is difficult	26
22	which it is difficult	26
23	[verb] it is difficult	25
24	as it is difficult	22
25	as it is difficult	22
26	because it is difficult	20
27	because it is difficult	20
28	since it is difficult	16
29	since it is difficult	16
30	[Wh adv] it is difficult	14