In the English Grammar Profile, C2 point 236 in the category of MODALITY is defined:
‘as’ + pronoun + ‘used to’ to add background to a narrative, often to highlight something unusual
*Note this is not the “as + adjective + as” structure.
Student example in a speaking test:
I don’t think that they pay enough attention towards the national customs as they used to do those days.
TLC female Sri Lanka B2
Expert example:
When soldiers came across roadside bombs in Iraq and Afghanistan,
instead of putting on a bomb suit and going out and poking with a stick, as they used to do up until about 2002,
A search in iWeb for:
as_C _P used_V _TO _VV
1 AS THEY USED TO SAY 269
2 AS WE USED TO SAY 249
3 AS WE USED TO CALL 200
4 AS I USED TO THINK 80
5 AS I USED TO WORK 65
6 AS I USED TO GET 65
7 AS WE USED TO KNOW 51
8 AS HE USED TO SAY 51
9 AS I USED TO CALL 48
10 AS I USED TO LIVE 48
11 AS THEY USED TO CALL 47
12 AS I USED TO LOVE 42
13 AS I USED TO SAY 42
14 AS I USED TO USE 40
15 AS I USED TO GO 34
16 AS WE USED TO THINK 33
17 AS I USED TO PLAY 32
18 AS HE USED TO PLAY 30
19 AS HE USED TO CALL 23
20 AS I USED TO MAKE 22
21 AS I USED TO TELL 21
22 AS I USED TO OWN 18
23 AS THEY USED TO THINK 17
24 AS I USED TO RUN 16
25 AS I USED TO SEE 15
26 AS I USED TO FEEL 15
27 AS I USED TO LIKE 14
28 AS I USED TO TAKE 14
29 AS I USED TO SUFFER 14
30 AS WE USED TO SEE 13
A2:
call, own
B1:
used to
B2:
suffer