SN4 ""

No	Pattern	Freq
1	[verb] once [art]	354
2	[verb] once a	206
3	[verb] once a	199
4	[vb pp] once [art]	121
5	[verb] once the	115
6	[verb] once the	115
7	[vb base] once [art]	51
8	[vb past] once [art]	45
9	[vb -s] once [art]	44
10	[vb infin] once [art]	41
11	[verb] once every	33
12	[verb] once every	33
13	[to-vb] once [art]	29
14	meet once [art]	27
15	[v-ing] once [art]	23
16	come once [art]	15
17	comes once [art]	8
18	hold once [art]	8
19	do once [art]	8
20	use once [art]	7
21	[verb] once an	7
22	visit once [art]	7
23	take once [art]	7
24	meets once [art]	7
25	met once [art]	7
26	happen once [art]	7
27	held once [art]	7
28	meet once [art]	7
29	update once [art]	6
30	occur once [art]	6