SN4 ""

No	Pattern	Freq
1	[vb mod] have been [prep] [det]	104
2	[modal v] have been [prep] [det]	104
3	[adv] have been [prep] [det]	37
4	must have been [prep] [det]	26
5	must have been [prep] [det]	26
6	would have been [prep] [det]	25
7	would have been [prep] [det]	23
8	could have been [prep] [det]	21
9	could have been [prep] [det]	21
10	[not/n't] have been [prep] [det]	19
11	not have been [prep] [det]	19
12	[adv] have been [prep] [det]	18
13	may have been [prep] [det]	13
14	may have been [prep] [det]	13
15	n't have been [prep] [det]	11
16	might have been [prep] [det]	10
17	might have been [prep] [det]	10
18	not have been [prep] [det]	8
19	well have been [prep] [det]	6
20	well have been [prep] [det]	6
21	never have been [prep] [det]	5
22	should have been [prep] [det]	5
23	never have been [prep] [det]	5
24	should have been [prep] [det]	5
25	have been [verb] [prep] [det]	326
26	have been [vb pp] [prep] [det]	299
27	have been [adj] [prep] [det]	180
28	have been [adj] [prep] [det]	153
29	have been [v-ing] [prep] [det]	26
30	have been [adv] [prep] [det]	21