SN4 ""

No	Pattern	Freq
1	[prep] once [prep] [noun]	65
2	[prep] once [prep] [noun]	65
3	[verb] once [prep] [noun]	65
4	at once [prep] [noun]	58
5	at once [prep] [noun]	58
6	[conj] once [prep] [noun]	38
7	[noun] once [prep] [noun]	37
8	[adv] once [prep] [noun]	37
9	[adv] once [prep] [noun]	33
10	[vb pp] once [prep] [noun]	30
11	[noun sg] once [prep] [noun]	23
12	[coord] once [prep] [noun]	21
13	[vb past] once [prep] [noun]	21
14	and once [prep] [noun]	19
15	and once [prep] [noun]	19
16	[be] once [prep] [noun]	16
17	be once [prep] [noun]	16
18	[was/were] once [prep] [noun]	15
19	was once [prep] [noun]	13
20	[pron] once [prep] [noun]	13
21	[pers pn] once [prep] [noun]	12
22	only once [prep] [noun]	12
23	only once [prep] [noun]	12
24	[subord] once [prep] [noun]	11
25	[noun pl] once [prep] [noun]	10
26	wash once [prep] [noun]	9
27	than once [prep] [noun]	8
28	than once [prep] [noun]	8
29	that once [prep] [noun]	6
30	[that] once [prep] [noun]	6