Теория:

Study some information about negative sentences and questions with 'to be able to' in present.
 
Для построения отрицательного предложения с to be able to в настоящем времени необходимо использовать следующий порядок слов:
subject \(+\) am/is/are \(+\) not \(+\) able to \(+\) Verb in the \(1\)st form (without 'to') \(+\) other parts of the sentence.
I am not able to swim across this river.
 
swim.JPG
 
Для построения общего и специального вопросов используйте следующий порядок слов.
  
General question
Am/ Is/Are \(+\) subject \(+\) able to \(+\) Verb in the \(1\)st form (without 'to') \(+\) other parts of the sentence?
Are you able to run a lot?
 
run.jpg
  
Special question
Question word (when, how, what....) \(+\) am/is/are \(+\) subject \(+\) able to \(+\) Verb in the \(1\)st form (without 'to') \(+\) other parts of the sentence?
What is he able to do for this team?
Источники:
http://gordsswimlog.blogspot.com/2011/08/swimming-in-warm-river-id.html
http://www.classical-music.com/article/classical-music-run