SN4 ""

No	Pattern	Freq
1	[conj] [adj] could have been	30
2	[prep] [adj] could have been	12
3	[noun] [adj] could have been	12
4	[prep] [adj] could have been	12
5	[adv] [adj] could have been	11
6	[adj] [adj] could have been	10
7	[that] [adj] could have been	10
8	that [adj] could have been	10
9	that [adj] could have been	10
10	[coord] [adj] could have been	10
11	[subord] [adj] could have been	10
12	[noun sg] [adj] could have been	7
13	[verb] [adj] could have been	7
14	but [adj] could have been	7
15	but [adj] could have been	7
16	[adv] [adj] could have been	7
17	[pron] [adj] could have been	6
18	the [adj] could have been	5
19	of [adj] could have been	5
20	[art] [adj] could have been	5
21	[art] [adj] could have been	5
22	the [adj] could have been	5
23	[det] [adj] could have been	5
24	of [adj] could have been	5
25	[adj] [noun] could have been	259
26	[adj] [noun sg] could have been	154
27	[adj] [noun pl] could have been	96
28	[adj] [pron] could have been	18
29	[adj] [conj] could have been	17
30	[adj] [pers pn] could have been	12