SN4 ""

No	Pattern	Freq
1	it is difficult [to-vb]	1523
2	it is difficult to see	185
3	it is difficult to imagine	78
4	it is difficult to know	62
5	it is difficult to believe	55
6	it is difficult to say	45
7	it is difficult to find	40
8	it is difficult to assess	40
9	it is difficult to avoid	31
10	it is difficult to understand	30
11	it is difficult to get	25
12	it is difficult to think	22
13	it is difficult to determine	21
14	it is difficult to distinguish	20
15	it is difficult to make	19
16	it is difficult to tell	17
17	it is difficult to identify	16
18	it is difficult to decide	16
19	it is difficult to predict	14
20	it is difficult to envisage	13
21	it is difficult to argue	13
22	it is difficult to accept	13
23	it is difficult to explain	13
24	it is difficult to define	12
25	it is difficult to separate	12
26	it is difficult to establish	12
27	it is difficult to compare	12
28	it is difficult to estimate	11
29	it is difficult to put	11
30	it is difficult to give	11