SN4 ""

No	Pattern	Freq
1	[modal v] have been difficult [prep]	22
2	[vb mod] have been difficult [prep]	22
3	would have been difficult [prep]	16
4	would have been difficult [prep]	16
5	have been [adv] difficult [prep]	8
6	have been [adv] difficult [prep]	8
7	have been difficult [to-vb] [prep]	6
8	have been difficult [verb] [prep]	6
9	have been difficult [prep] [art]	10
10	have been difficult [prep] [art]	10
11	have been difficult [prep] the	8
12	have been difficult [prep] the	8
13	have been difficult [prep] [pron]	7
14	have been difficult [prep] [pers pn]	5