阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使 用括号中词语的正确形式填空。
    A group of boys stood around a tree. " （1）

What

What

a tall tree!" They said to each other.""It would be exciting to climb to the top."
    The group of boys then wanted to play a game to see who could climb to the top of the tree first.Their mothers were （2）

sitting

sitting

（sit） not far away，looking at their children as they played.
    One of the （3）

kids

kids

（boy） was an 8-year-old boy named David.He was the （4）

shortest

shortest

（short） in the group.Nobody thought he could win the competition.
    Then the game started All of the boys tried their best.David didn't climb fast （5）

at

at

first，but he was the first to get to the top in the end.
    His mother was proud She asked，"David，how did you get to the top of the tree so （6）

quickly

quickly

（quick）？"
    "It was easy，" David said，"the other boys were looking （7）

down

down

when they climbed.They were so afraid （8）

that

that

they couldn't climb fast.But I was looking up when I climbed.I was happy （9）

to find

to find

（find ） I was close to the top，so I climbed fast."
    It is true in life that （10）

if

if

we just keep going up and never look back，we will probably make our dreams come true.