背诵为王第三册第36课 Look Quickly

Lesson36 Look Quickly
Jack joined the Boy Scouts when he was twelve. The teachers were very nice, and Jack began to learn a lot of useful things, so he was very happy.
One day the teacher came to the camp to teach Jack and the other young Scouts to read a map. He showed them what represented a river and how to find out the elevation. "Now," the teacher went on, "how can we find out whether we can see one place from another?" Nobody answered. "Well," the teacher continued, "if there's a higher place on a straight line between them, it will be impossible for us to see one from the other, won't it?"
The teacher continued to question the boys. "Do you see the tree on this mountain over here?" He pointed it out to the boys. "It's 120 meters above sea level. Here's the problem for you: if I was beside the tree, and you were in the middle of the river, Jack, would I be able to see you?
Jack looked at the map carefully and then answered, "Yes, sir, you definitely would — if you looked very quickly."
The teacher was surprised. "What nonsense!" he said." What ever do you mean?There's nothing between the tree and the river which is so high that it prevents me from seeing you, so why would I have to look quickly?"
"Because I can't swim," Jack answered.

Boy Scouts 男童子军
elevation 海拔
represent 代表，表示

赶快看
杰克十二岁时参加了男童子军。老师们都很和蔼，而且杰克学到很多有用的知识，所以他很开心。
一天，有个老师来到营地教杰克和其他小童子军识别地图。他告诉他们什么代表河流以及如何算出海拔。“现在，”老师接着说，“我们怎样知道能否从某地看到另一地？”
无人应答。
“这样，”老师继续道，“如果有一较高的地方位于两地之间的一条直线上，我们就不可能从此地看到彼地，是不是啊？”
老师接着提问男孩们：“你们看到这边这座山上的树吗？”他指给男孩们看，“它高于海平面一百二十米。现在的问题是：如果我在树旁边，而你在河的中间，杰克，我能不能看到你？”
杰克仔细看看地图，然后回答：“是的，先生，你肯定能看到——如果你赶快看的话。”
老师很惊讶。“无稽之谈！”他说，“你想说什么？树和河之间没有任何高到足以阻碍我看到你的东西，我为什么必须赶快看？”
“因为我不会游泳，”杰克答道。