SN4 ""

No	Pattern	Freq
1	[pers pn] [vb mod] have been [adj]	1902
2	[pers pn] [modal v] have been [adj]	1416
3	it [modal v] have been [adj]	1047
4	[pers pn] would have been [adj]	1003
5	[pers pn] would have been [adj]	913
6	[pers pn] must have been [adj]	315
7	[pers pn] must have been [adj]	315
8	he [modal v] have been [adj]	247
9	[pers pn] [modal v] have been [adj -er]	237
10	[pers pn] might have been [adj]	201
11	[pers pn] might have been [adj]	201
12	i [modal v] have been [adj]	181
13	[pers pn] could have been [adj]	163
14	[pers pn] could have been [adj]	163
15	she [modal v] have been [adj]	152
16	[pers pn] [modal v] have been good	140
17	[pers pn] [modal v] have been [num]	138
18	they [modal v] have been [adj]	130
19	[pers pn] [modal v] have been better	124
20	[pers pn] may have been [adj]	112
21	[pers pn] may have been [adj]	112
22	[pers pn] [modal v] have been able	109
23	[pers pn] [modal v] have been able	109
24	[pers pn] [modal v] have been [det]	102
25	[pers pn] should have been [adj]	92
26	[pers pn] should have been [adj]	92
27	[pers pn] 'd have been [adj]	90
28	you [modal v] have been [adj]	67
29	[pers pn] [modal v] have been easy	58
30	we [modal v] have been [adj]	56