Why _ing is here?
Hello,

Could you help me please?

What is the rule for using -ing in the following sentences? It seems to be because of "to be used to + ing", right?

Australian are used to driving on the right side
Lisa get used to living in Germany …

Thank you

Question

Why _ing is here?
Hello,

Could you help me please?

What is the rule for using -ing in the following sentences? It seems to be because of "to be used to + ing", right?

Australian  are used to driving on the right side 
Lisa get used to living in Germany …

Thank you

Answer

Yes, in certain cases "to" acts as a proper preposition and not part of an infinitive verb.  "To be/get used to _ing" is one of these cases.

If you want to check if you really need _ing for the verb, try putting a noun after "to". If the sentence still makes sense, then you need a gerund (_ing) form.

Australians are used to [different road rules]. 
Lisa has got used to [a German lifestyle].
I'm used to [hot weather].
I can't get used to [the noise].

Answer

-ing is gerund in this case. those sentences means that somebody do something early, but don't do it now