Three letters certainty are confusing you.

7년 전

 
According to my experience in teaching Arabic to many people around the world, I can tell you what are these Arabic letters confusing you : 
1.  'ع" Do you think you pronounce "ع"  properly!  maybe you are saying it "أ"    
2. "ح"   this is the stronger sister of  هـ So make you sure you're saying  ح not its sister 
3. "ض"   Maybe you think that ض is easy for you.. 
 if there is another Arabic letter confusing you, I'd like to  know it.