SN4 ""

No	Pattern	Freq
1	[be] [adv] difficult	3732
2	be [adv] difficult	3732
3	[be] [adv] difficult	3351
4	[is] [adv] difficult	2051
5	is [adv] difficult	1587
6	[be] very difficult	1044
7	[be] very difficult	1044
8	[be] [adv] difficult	636
9	be [adv] difficult	636
10	[was/were] [adv] difficult	567
11	[be] more difficult	528
12	[be] more difficult	528
13	was [adv] difficult	478
14	's [adv] difficult	464
15	[be] [not/n't] difficult	380
16	[be] not difficult	379
17	[am/are] [adv] difficult	368
18	are [adv] difficult	361
19	[be] not difficult	321
20	[be] extremely difficult	271
21	[be] extremely difficult	271
22	[be] often difficult	170
23	[be] often difficult	170
24	[be] so difficult	136
25	[be] so difficult	136
26	[be] quite difficult	133
27	[be] quite difficult	133
28	[be] too difficult	133
29	[be] too difficult	133
30	been [adv] difficult	97