Предлагаю варианты вопросов, аналогично примеру с Marina.
  - Anton is three.
 
  
   - (a) Is Anton three?
 
   - (b) How old is Anton?
 
  
  - Tamara is eleven.
 
   
    - (a) Is Tamara eleven?
 
    - (b) How old is Tamara?
 
   
  - The children are twelve.
 
   
    - (a) Are the children twelve?
 
    - (b) How old are the children?
 
   
  - The boys are sixteen.
 
   
    - (a) Are the boys sixteen?
 
    - (b) How old are the boys?