有关心前区震颤正确的是（） A.常见于二尖瓣关闭不全 B.常见于主动脉瓣关闭不全 C

    Learning is  natural.  It begins the   1  we are  born.  Our first  teachers are our f amilies. At  home  we 
learn  to talk and to    2    and feed ourselves. We learn these and other skills by  3     .
    Then we go to school.  Many  teachers teach us     4    to learn and  how to learn. And we pass  many
tests and exams. People say we are educated. Are we really educated? Let's think about the real meaning  of    5  .  Knowing facts doesn't mean being  able to solve problems.  Solving  problems    6      creativity,
not just good memory.
    What does a good  teacher do? Does he give  students facts to    7   ?Well,  yes,  we must  sometimes
remember  facts.  But a good teacher   8  how  to find answers. He brings us to the   9    of   knowledge
where we can drink for ourselves. When we are thirsty, we know   10   to go.
    True  learning combines  in-take with  out-put. We take information into our brains. Then we use it, a
person who only remembers facts hasn't really learned. Learning  takes place only  when a  person  cap
use what he knows.