SN4 ""

No	Pattern	Freq
1	have [been] shown to be	176
2	[verb] [been] shown to be	176
3	has [been] shown to be	100
4	[vb -s] [been] shown to be	100
5	have [been] shown to be	62
6	[vb base] [been] shown to be	62
7	[adv] [been] shown to be	40
8	[adv] [been] shown to be	37
9	[vb past] [been] shown to be	13
10	had [been] shown to be	13
11	previously [been] shown to be	8
12	previously [been] shown to be	8
13	also [been] shown to be	7
14	also [been] shown to be	7
15	recently [been] shown to be	5
16	recently [been] shown to be	5
17	[been] shown to be [adj]	102
18	[been] shown to be [adj]	96
19	[been] shown to be [adv]	54
20	[been] shown to be [adv]	51
21	[been] shown to be [art]	30
22	[been] shown to be [art]	30
23	[been] shown to be [verb]	24
24	[been] shown to be a	23
25	[been] shown to be [vb pp]	22
26	[been] shown to be a	18
27	[been] shown to be effective	14
28	[been] shown to be effective	14
29	[been] shown to be [noun]	6
30	[been] shown to be more	6