SN4 ""

No	Pattern	Freq
1	[that] [vb mod] have been [adj]	57
2	[that] [modal v] have been [adj]	57
3	that [modal v] have been [adj]	57
4	[that] [modal v] have been [adj]	51
5	[that] would have been [adj]	36
6	[that] would have been [adj]	36
7	[that] must have been [adj]	6
8	[that] should have been [adj]	6
9	[that] might have been [adj]	6
10	[that] should have been [adj]	6
11	[that] [modal v] have been unthinkable	6
12	[that] [modal v] have been unthinkable	6
13	[that] must have been [adj]	6
14	[that] might have been [adj]	6
15	[that] [modal v] have been impossible	5
16	[that] [modal v] have been impossible	5