SN4 ""

No	Pattern	Freq
1	been operating [prep]	60
2	been operating [prep]	60
3	been operating in	20
4	been operating in	20
5	been operating for	18
6	been operating for	18
7	been operating [adv]	13
8	been operating [adv]	11
9	been operating [art]	8
10	been operating [art]	8
11	been operating since	7
12	been operating since	7
13	been operating a	7
14	been operating a	6
15	[verb] been operating	92
16	have been operating	92
17	[vb -s] been operating	42
18	has been operating	42
19	have been operating	23
20	[vb base] been operating	23
21	had been operating	19
22	[vb past] been operating	19
23	[adv] been operating	7
24	[adv] been operating	7
25	have been operating	5
26	[vb infin] been operating	5