SN4 ""

No	Pattern	Freq
1	[be] very difficult	1044
2	be very difficult	1044
3	[is] very difficult	598
4	is very difficult	359
5	[pron] very difficult	241
6	's very difficult	239
7	[art] very difficult	233
8	[art] very difficult	233
9	[pers pn] very difficult	229
10	be very difficult	227
11	[be] very difficult	227
12	it very difficult	222
13	it very difficult	222
14	a very difficult	220
15	a very difficult	220
16	[adv] very difficult	131
17	[was/were] very difficult	121
18	[adv] very difficult	117
19	was very difficult	104
20	[verb] very difficult	102
21	[noun] very difficult	75
22	[am/are] very difficult	55
23	[noun sg] very difficult	53
24	are very difficult	52
25	[adj] very difficult	51
26	[det] very difficult	46
27	[been] very difficult	43
28	been very difficult	43
29	[conj] very difficult	32
30	[coord] very difficult	31