SN4 ""

No	Pattern	Freq
1	[modal v] have been [noun]	660
2	[vb mod] have been [noun]	660
3	would have been [noun]	195
4	would have been [noun]	185
5	[adv] have been [noun]	156
6	must have been [noun]	117
7	[adv] have been [noun]	117
8	must have been [noun]	117
9	may have been [noun]	110
10	may have been [noun]	110
11	might have been [noun]	97
12	might have been [noun]	97
13	could have been [noun]	93
14	could have been [noun]	93
15	not have been [noun]	39
16	[not/n't] have been [noun]	39
17	should have been [noun]	38
18	should have been [noun]	38
19	well have been [noun]	30
20	well have been [noun]	30
21	not have been [noun]	27
22	n't have been [noun]	12
23	easily have been [noun]	11
24	easily have been [noun]	11
25	[pron] have been [noun]	11
26	[pers pn] have been [noun]	11
27	'd have been [noun]	10
28	will have been [noun]	10
29	it have been [noun]	10
30	it have been [noun]	10