SN4 ""

No	Pattern	Freq
1	[pron] must have [been] the [adj]	33
2	[pers pn] must have [been] the [adj]	22
3	it must have [been] the [adj]	15
4	it must have [been] the [adj]	15
5	[noun] must have [been] the [adj]	13
6	[Wh det] must have [been] the [adj]	10
7	what must have [been] the [adj]	8
8	[noun sg] must have [been] the [adj]	8
9	what must have [been] the [adj]	8
10	[adj] must have [been] the [adj]	7
11	[det] must have [been] the [adj]	6
12	must have [been] [prep] the [adj]	18
13	must have [been] [prep] the [adj]	18
14	must have [been] the [adv] [adj]	7
15	must have [been] the [adv] [adj]	7
16	must have [been] the most [adj]	5
17	must have [been] the most [adj]	5
18	must have [been] the [adj] [noun]	42
19	must have [been] the [adj] [noun sg]	41
20	must have [been] the [adj] [pron]	5