Originally Posted by 760831
There are not fixed rules as how to use the structure you mention.
They are just fixed phrases you have to learn taking into account the meaning of each of them.
As from/of Monday you won't be able to go to school without your uniform.
As for/to the uniform, you can ask Mrs Johnson where to buy it .
He earns $80 000 a year, as against (=compared) my $40 000.
Hope this helps, Maeve