英语高手来,语法填空.Do you feel ___ difficult to be happy all the tim

英语高手来,语法填空.
Do you feel ___ difficult to be happy all the time?Now i will give you some tips___ how to make yourself happy.one way is being ___(self)because unselfishness is the key factor ___(require) if youwant to get along well with others.by ___(say) being unselfish we mean we___ not want everything our own way or demand the best share of everything.anotherwayistn look for good point in ___ people.