‘AT‘ is by far the most common as a simple preposition. (II)
2 AT is also used in two-part adverbial phrases. (RR21)
1 AT ALL 1232801
Maybe they weren’t thinking about anything at all.
2 AT FIRST 403759
At first, I thought they worked for the government.
3 AT ONCE 222526
4 AT BEST 111972
5 AT PRESENT 83432
6 AT LAST 77484
7 AT MOST 61078
8 AT LARGE 57046
9 AT RANDOM 36452
10 AT LENGTH 32751
5 AT (RR32)
ALL AT ONCE 54444
I think Sarah threw a little too much information at David all at once.
6 AT (RR31)
AT LONG LAST 7739