SN4 ""

No	Pattern	Freq
1	[prep] once [prep] [art]	158
2	[prep] once [prep] [art]	158
3	at once [prep] [art]	139
4	at once [prep] [art]	139
5	[conj] once [prep] [art]	120
6	[adv] once [prep] [art]	114
7	[verb] once [prep] [art]	106
8	[adv] once [prep] [art]	95
9	[noun] once [prep] [art]	80
10	[noun sg] once [prep] [art]	57
11	[coord] once [prep] [art]	56
12	[subord] once [prep] [art]	52
13	than once [prep] [art]	50
14	than once [prep] [art]	50
15	[vb pp] once [prep] [art]	40
16	[pron] once [prep] [art]	37
17	[be] once [prep] [art]	36
18	be once [prep] [art]	36
19	and once [prep] [art]	34
20	and once [prep] [art]	34
21	[was/were] once [prep] [art]	32
22	[pers pn] once [prep] [art]	31
23	only once [prep] [art]	30
24	only once [prep] [art]	30
25	[vb past] once [prep] [art]	30
26	least once [prep] [art]	27
27	least once [prep] [art]	27
28	was once [prep] [art]	22
29	but once [prep] [art]	21
30	but once [prep] [art]	21