SN4 ""

No	Pattern	Freq
1	difficult [verb] the [adj] [noun]	166
2	difficult [to-vb] the [adj] [noun]	165
3	difficult [verb] the [adj] [noun sg]	116
4	difficult [verb] the [adj] [noun pl]	47
5	difficult [verb] the precise [noun]	11
6	difficult get the [adj] [noun]	8
7	difficult to get the [adj] [noun]	8
8	difficult to assess the [adj] [noun]	7
9	difficult [verb] the right [noun]	7
10	difficult assess the [adj] [noun]	7
11	difficult [verb] the [adj] effect	7
12	difficult to determine the [adj] [noun]	6
13	difficult to see the [adj] [noun]	6
14	difficult [verb] the exact [noun]	6
15	difficult determine the [adj] [noun]	6
16	difficult see the [adj] [noun]	6
17	difficult maintain the [adj] [noun]	5
18	difficult [verb] the real [noun]	5
19	difficult to maintain the [adj] [noun]	5
20	difficult find the [adj] [noun]	5
21	difficult [verb] the [adj] effect	5