英语用An造句

   I buy an apple for my sister.

   I am taking an airplane with my friend to a trip this summer vaction.. 

   I want to be an Enginer in my future..

   I can give you an idea to solve for this math question.. 

   I am drawing an orange in my art class.

   I  am watching an interesting movie.

   I bought an eraser.

   I have an uncle.

   Australia is an English speaking nation. 

   I always rest for an hour after dinner. 

   The city is at an elevation of 2000 metres.