SN4 ""

No	Pattern	Freq
1	difficult to see	416
2	difficult to get	342
3	difficult to find	290
4	difficult to understand	205
5	difficult to say	174
6	difficult to imagine	171
7	difficult to achieve	167
8	difficult to know	158
9	difficult to believe	153
10	difficult to assess	151
11	difficult to make	150
12	difficult to obtain	123
13	difficult to explain	121
14	difficult to do	121
15	difficult to tell	120
16	difficult to keep	116
17	difficult to determine	115
18	difficult to distinguish	104
19	difficult to establish	90
20	difficult to define	86
21	difficult to accept	84
22	difficult to predict	78
23	difficult to interpret	76
24	difficult to identify	76
25	difficult to avoid	75
26	difficult to control	75
27	difficult to maintain	71
28	difficult to cope	67
29	difficult to judge	66
30	difficult to put	63