6.
a) A third reason why s/he is my best friend is that we share many principles.
b) For example, we both believe that we should not damage our health by smoking cigarettes.
7.
a) Lastly, I believe that XXX has had a positive influence on my life since we have met.
b) XXX is always friendly, cares about his/her family and friends, and is always willing to listen to others.
So now you know why XXX is my best friend.
