Теория:

Study the information about verb + to.
  
1. Use to (infinitive) after these verbs:

Learn, promise, threaten, deserve, afford, forget, hope, manage, fail,
decide, plan, arrange, offer, agree, refuse.
  
Mary was in a difficult situation, so I agreed to help her.
  
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It was too late, so we decided to take a taxi.
 
2. The negative is not to:

They decided not to go out because of the football match on TV.
  
3. After some verbs (enjoy, think, suggest), to is not possible.

4. We use to after these verbs: seem, appear, tend, pretend, claim.

Sally pretended not to see me when she passed me in the street.
  
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5. The infinitive can be: continuous (to be doing) and perfect (to have done).

She pretended to be reading the newspaper.
  
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6. If you say dare, the use of to is optional.

She would not dare to tell him the truth.

She would not dare tell him the truth.

7. After these verbs (ask, decide, know, remember, forget, explain, learn, understand, wonder), you can use a question word (what, whether, how etc.) +to.
 
We asked how to get to the bus station.
 
Remember!

Show, tell, advise, teach somebody what/how/where to do something.
Источники:
abta.com
en.wikipedia.org
www.flickr.com