SN4 ""

No	Pattern	Freq
1	[noun] must be [prep]	502
2	[pron] must be [prep]	436
3	[pers pn] must be [prep]	361
4	[noun sg] must be [prep]	327
5	it must be [prep]	189
6	it must be [prep]	189
7	[noun pl] must be [prep]	134
8	they must be [prep]	52
9	they must be [prep]	51
10	[adj] must be [prep]	40
11	he must be [prep]	34
12	he must be [prep]	34
13	[ex0] must be [prep]	33
14	there must be [prep]	33
15	there must be [prep]	33
16	[noun prp] must be [prep]	32
17	you must be [prep]	30
18	you must be [prep]	30
19	[det] must be [prep]	29
20	[Wh det] must be [prep]	26
21	which must be [prep]	23
22	which must be [prep]	23
23	[adv] must be [prep]	21
24	i must be [prep]	21
25	i must be [prep]	21
26	she must be [prep]	19
27	she must be [prep]	19
28	[adv] must be [prep]	18
29	[verb] must be [prep]	18
30	[conj] must be [prep]	18