SN4 ""

No	Pattern	Freq
1	[pron] could have been	1255
2	[pers pn] could have been	975
3	[noun] could have been	824
4	[noun sg] could have been	518
5	it could have been	502
6	it could have been	502
7	[noun pl] could have been	219
8	he could have been	155
9	he could have been	155
10	[adj] could have been	151
11	[Wh det] could have been	138
12	[conj] could have been	133
13	[det] could have been	127
14	they could have been	91
15	which could have been	88
16	which could have been	88
17	they could have been	85
18	she could have been	81
19	she could have been	80
20	[noun prp] could have been	76
21	that could have been	75
22	that could have been	75
23	[that] could have been	75
24	there could have been	72
25	there could have been	72
26	[ex0] could have been	72
27	i could have been	69
28	i could have been	68
29	this could have been	51
30	this could have been	51