When we think about happiness, we usually think of something extraordinary, a pinnacle(顶点) of sheer(纯粹的) delight. And those pinnacles seem to get rarer the older we get.
   I remember playing police and robbers in the woods, getting a speaking part in the school play. Of course, kids also experience lows, but their delight at such peaks of pleasure as winning a race or getting a new bike is unreserved.
For teenagers, or people under 20 the concept of happiness changes.    I can still feel the pain of not being invited to a party that almost everyone else was going to. I also remember the great happiness of being invited at another event to dance with a very handsome young man.
In adulthood the things that bring great joy—birth, love, marriage—also bring responsibility and the risk of loss.   For adults, happiness is complex.
   But I think a better definition of happiness is “ the ability to enjoy something”. The more we can enjoy what we have, the happier we are. It's easy to overlook the pleasure we get from loving and being loved, the company of friends, the freedom to live where we please, even good health.
While happiness may be more complex for us, the solution is the same as ever. Happiness isn't about what happens to us; it’s the ability to find a positive for every negative, and view a difficulty as a challenge.  

A．Love may not last; loved ones die.

B．For a child, happiness has a magic quality.

C．Happiness is the meaning and the purpose of life.

D．Being happy doesn’t mean that everything is perfect.

E. The dictionary defines “happy” as “lucky” or “fortunate”.
F. It's not wishing for what we don't have, but enjoying what we do possess.
G. Suddenly it’s conditional on such things as excitement, love, and popularity.