SN4 ""

No	Pattern	Freq
1	[noun] at a [noun] [prep]	1980
2	[verb] at a [noun] [prep]	1701
3	[noun sg] at a [noun] [prep]	1243
4	[vb pp] at a [noun] [prep]	680
5	[noun pl] at a [noun] [prep]	534
6	[v-ing] at a [noun] [prep]	370
7	[adv] at a [noun] [prep]	342
8	[vb past] at a [noun] [prep]	270
9	[adv] at a [noun] [prep]	230
10	[adj] at a [noun] [prep]	218
11	be at a [noun] [prep]	191
12	[be] at a [noun] [prep]	191
13	look at a [noun] [prep]	184
14	[noun prp] at a [noun] [prep]	153
15	[conj] at a [noun] [prep]	136
16	[to-vb] at a [noun] [prep]	114
17	[pron] at a [noun] [prep]	105
18	[adv prt] at a [noun] [prep]	104
19	[coord] at a [noun] [prep]	103
20	[num] at a [noun] [prep]	99
21	[vb base] at a [noun] [prep]	94
22	[vb -s] at a [noun] [prep]	93
23	arrive at a [noun] [prep]	93
24	[adj] at a [noun] [prep]	83
25	[vb infin] at a [noun] [prep]	80
26	[was/were] at a [noun] [prep]	75
27	looking at a [noun] [prep]	74
28	[pers pn] at a [noun] [prep]	68
29	was at a [noun] [prep]	61
30	and at a [noun] [prep]	60