SN4 ""

No	Pattern	Freq
1	at an [adj] [noun sg]	2058
2	at an [adj] [noun]	1945
3	at an early [noun]	617
4	at an early [noun]	479
5	at an [adj] stage	420
6	at an [adj] stage	420
7	at an [adj] rate	194
8	at an [adj] rate	194
9	at an [adj] age	151
10	at an [adj] age	151
11	at an [adj -er] [noun]	145
12	at an earlier [noun]	138
13	at an [adj] level	132
14	at an [adj] level	132
15	at an [adj] cost	116
16	at an [adj] cost	116
17	at an annual [noun]	89
18	at an annual [noun]	89
19	at an [adj] date	64
20	at an [adj] date	64
21	at an average [noun]	62
22	at an average [noun]	62
23	at an additional [noun]	55
24	at an additional [noun]	55
25	at an [adj] time	53
26	at an appropriate [noun]	53
27	at an appropriate [noun]	53
28	at an [adj] time	53
29	at an [adj] meeting	52
30	at an [adj] meeting	52