SN4 ""

No	Pattern	Freq
1	which [vb mod] have been	707
2	which [modal v] have been	694
3	which would have been	241
4	which would have been	241
5	which may have been	120
6	which may have been	120
7	which could have been	88
8	which could have been	88
9	which should have been	82
10	which should have been	82
11	which might have been	79
12	which might have been	79
13	which must have been	64
14	which must have been	64
15	which will have been	16
16	which will have been	16
17	which ought have been	12
18	which ought have been	12
19	which [modal v] to have been	12