1.
  As she is rich, she can buy a new car.
-> , she can buy a new car.
 
   
 
2.
  Though I accepted his idea, I didn't like his manners.
-> , I didn't like his manners.
 
   
 
3.
  Because it is used by everyone, it should be placed in the hallway.
-> , it should be placed in the hallway.