SN4 ""

No	Pattern	Freq
1	[conj] [pron] could have been [prep]	16
2	[coord] [pron] could have been [prep]	9
3	[verb] [pron] could have been [prep]	7
4	but [pron] could have been [prep]	7
5	but [pron] could have been [prep]	7
6	[noun] [pron] could have been [prep]	6
7	[subord] [pron] could have been [prep]	5
8	[pron] could [adv] have been [prep]	20
9	[pron] could not have been [prep]	13
10	[pron] could [not/n't] have been [prep]	13
11	[pron] could not have been [prep]	8
12	[pron] could [adv] have been [prep]	7
13	[pron] could n't have been [prep]	5
14	[pron] could have been [verb] [prep]	188
15	[pron] could have been [vb pp] [prep]	163
16	[pron] could have been [adj] [prep]	46
17	[pron] could have been [adj] [prep]	27
18	[pron] could have been [v-ing] [prep]	24
19	[pron] could have been [adv] [prep]	15
20	[pron] could have been [adv] [prep]	11
21	[pron] could have been make [prep]	9
22	[pron] could have been [noun] [prep]	8
23	[pron] could have been used [prep]	8
24	[pron] could have been made [prep]	8
25	[pron] could have been use [prep]	8
26	[pron] could have been [adj -er] [prep]	7
27	[pron] could have been [num] [prep]	7
28	[pron] could have been do [prep]	7
29	[pron] could have been done [prep]	6
30	[pron] could have been [pron] [prep]	6