What should I say "to get" or "to getting"?
"The key to getting teenagers to respect you is to respect them first" I found this phrase in an English books. I thought that always after "to" I have to say the verb without "-ing". I meant "The key to get..."

I got confused about this topic I will really appreaciate if you help me. Could you, please? Thank you in advanced

Question

What should I say "to get" or "to getting"?
"The key to getting teenagers to respect you is to respect them first" I found this phrase in an English books. I thought that always after "to" I have to say the verb without "-ing". I meant "The key to get..."
 
I got confused about this topic I will really appreaciate if you help me. Could you, please? Thank you in advanced

Answer

I agree with Bryan and Francesca about the grammar. Whether it is a preposition or gerund, 
You can also say " they key to get teenagers to respect you..." and this would be correct, but less popular. Adding 'ing is more common, but a less lazy verb would be better.

Answer

Thank you everyone

Answer

I agree with Bryan, but also want to say that you should try to use another verb rather than 'get'.   'Get' is a lazy verb, there are so many more useful verbs out there.   I would use 'gain', 'obtain' or even 'have'.   I don't think the sentence is written correctly anyway.   It should read:  The key to having teenagers respect you is to respect them first.

Answer

This is one of those weird english grammar situation where 'to' is used as a preposition to show movement towards a condition or state (getting teenagers to respect you), and not as an infinitive marker.

When 'to' is used as a preposition, the infinitive of a verb does not have to be used afterwards; it can be modified to fit the tense.