SN4 ""

No	Pattern	Freq
1	[modal v] have [been] [adj] for	273
2	[modal v] have been [adj] for	273
3	[vb mod] have [been] [adj] for	273
4	[modal v] have [been] [adj] for	271
5	[modal v] have [been] [adj] for	241
6	would have [been] [adj] for	146
7	would have [been] [adj] for	144
8	must have [been] [adj] for	48
9	must have [been] [adj] for	48
10	[modal v] have [been] responsible for	39
11	[modal v] have [been] responsible for	39
12	[modal v] have [been] [adj -er] for	30
13	may have [been] [adj] for	29
14	may have [been] [adj] for	29
15	[modal v] have [been] good for	28
16	might have [been] [adj] for	24
17	might have [been] [adj] for	24
18	[modal v] have [been] difficult for	20
19	[modal v] have [been] difficult for	20
20	[modal v] have [been] easy for	19
21	[modal v] have [been] better for	18
22	could have [been] [adj] for	15
23	could have [been] [adj] for	15
24	[modal v] have [been] easy for	15
25	[modal v] have [been] possible for	14
26	[modal v] have [been] possible for	14
27	[modal v] have [been] impossible for	12
28	[modal v] have [been] impossible for	12
29	[modal v] have [been] good for	9
30	[modal v] have [been] necessary for	8