SN4 ""

No	Pattern	Freq
1	[vb mod] have been [adj] for	240
2	would have been [adj] for	125
3	would have been [adj] for	123
4	must have been [adj] for	47
5	must have been [adj] for	47
6	[modal v] have been responsible for	39
7	may have been [adj] for	28
8	may have been [adj] for	28
9	[modal v] have been difficult for	20
10	might have been [adj] for	20
11	might have been [adj] for	20
12	[modal v] have been easy for	15
13	[modal v] have been possible for	14
14	[modal v] have been impossible for	12
15	could have been [adj] for	10
16	could have been [adj] for	10
17	[modal v] have been good for	9
18	[modal v] have been necessary for	8
19	should have been [adj] for	7
20	should have been [adj] for	7
21	[modal v] have been eligible for	6
22	[modal v] have been hard for	6
23	[modal v] have been terrible for	5