SN4 ""

No	Pattern	Freq
1	have once [been]	403
2	[verb] once [been]	403
3	[vb past] once [been]	384
4	had once [been]	375
5	[adv] once [been]	18
6	[adv] once [been]	15
7	'd once [been]	9
8	only once [been]	9
9	only once [been]	9
10	[v-ing] once [been]	7
11	having once [been]	7
12	once [verb] [been]	93
13	once have [been]	93
14	once have [been]	69
15	once [vb infin] [been]	69
16	once [vb past] [been]	23
17	once had [been]	23
18	once [adv] [been]	15
19	once [adv] [been]	15
20	once again [been]	10
21	once again [been]	10
22	once more [been]	5
23	once more [been]	5
24	once [been] [art]	146
25	once [been] [art]	146
26	once [been] a	98
27	once [been] a	87
28	once [been] [verb]	86
29	once [been] [vb pp]	82
30	once [been] [adj]	59