阅读下面短文，掌握其大意，然后从1~20各小题所给的四个选项A、B、C和D中，选出一个最佳答案。
One effective way of destroying happiness is to look at something and focus on even the smallest fault. It’s like looking at the tiled(铺瓦) ceiling and concentrating on the space where one tile is      .
Once I heard a bald man said, “whenever I enter a room       I see is hair.” Once you’ve       what your missing tile is, explore whether acquiring it will       make you happy. Then do one of the three things: Get it, replace it with a different      , or forget about it and       the tiles in your life that are not missing.
We all know people who have a relatively       life, yet are essentially unhappy while people who have suffered a great deal but       remain happy.
The first       is gratitude. All happy people are      . Ungrateful people cannot be happy. We tend to think that being unhappy leads people to      , but it’s truer to say that complaining leads people to becoming unhappy.
The second secret is            that happiness is a byproduct of something else. The most obvious________ are those pursuits that give our lives purpose—anything       studying insects to playing baseball. The more passions we have, the more happiness we are  ________  to experience.
Finally, the belief that something permanent goes beyond us and that our ________  has some larger meaning can help us to feel happier. We ________  a spiritual faith, or a philosophy; it should   ________ this truth: if you choose to find the ________  in every situation, you will be blessed, and if you choose to find the awful, you will be cursed. As with happiness itself, this is ________   your decision to make.

A．different B．missing C．short D．broken

A．nothing B．none C．all D．anything

A．determined B．predicted C．assumed D．imagined

A．completely B．naturally C．hopefully D．really

A．tile B．brick C．ceiling D．house

A．look on B．focus on C．count on D．rely on

A．peaceful B．difficult C．easy D．ordinary

A．certainly B．merely C．hardly D．generally

A．secret B．factor C．rule D．key

A．wealthy B．grateful C．proud D．generous

A．upset B．quarrel C．complain D．depress

A．admitting B．assuming C．proving D．realizing

A．sources B．results C．answers D．goals

A．among B．from C．through D．for

A．probable B．possible C．likely D．capable

A．value B．destination C．survival D．existence

A．need B．lack C．demand D．expect

A．involve B．include C．absorb D．mean

A．worst B．best C．positive D．negative

A．absolutely B．totally C．exactly D．largely