阅读理解

    Whenever the sun dropped and the blue sky came up, my father and I used to climb the mountain near my house. Walking together, my father and I used to have a lot of conversations, and I learnt lessons from his experiences during our conversations. He always told me, "You should have goals (目标) like climbing the mountain. "Without the mountain-climbing, we couldn't have enough time to spend together, because my father was very busy. I really got a lot from the mountain-climbing. It gave me time to talk with my father and to be in deep thoughts as well as to develop my patience.

    Once we climbed a very high mountain. It was so challenging for me because I was only ten years old. During the first few hours of climbing, I enjoyed the flowers and trees, and the birds' singing. But as time passed, I got a pain in both of my legs. I didn't want to climb. In fact, I hated it at that moment, but my father said to me, "You can always see a beautiful sky at the top of the mountain, but you can't see it before you reach the top. Only there at the top can you see all the nice things, just like in life."

    At that time, I was too young to understand his words. But later, I got to know hope and confidence (信心). I found myself standing at the top of the mountain, and the sky was as clear as the crystal (水晶).

如图，B点为海岸上一棵椰子树的顶点，请画出人在水下A点看到B点的光路图，并大致确定B点的像的位置B′．