_i am swimming in the sea 
_he is reading a book 
_you are a student 
_she is a nurse 
_you are not studying 
_she isn't at home 
_he is not at the school 
_we are on the beach 
_i am in a party 
_he is reading a magazine
Are you a student? = eres un estudiante? Is he at the library? = esta el en la biblioteca? Are they construction workers? = son ellos trabajadores de construccion? Am I sick? = estoy enferma/enfermo? 
@ Irene -Are we play tenis? > Do we play tennis? -Is he read the book? Does he read a book? Is he reading a book? Are you sleep? > Are tou asleep? Are you sleepy?