As a child, I started learning to play the piano, my favorite musical 1 but I was forced to give up when I started my middle school2 I could concentrate more on my studies.

    It's one of my biggest3 to stop practicing the piano when I recall sadly today. During the following years, I kept telling my piano teacher that I would4However, I didn't keep my promise because I was 5 with my study6 I lost touch with my teacher. Some years later, my teacher died. I was very sad because I lost such a good teacher. She was a very warm and gentle person. It hurts me to think she may have been 7 that I never returned. I haven't taken lessons since then but to be honest, I 8 to. Sitting at the piano, I couldn't help recalling many 9 ---times of my practising at home and playing before my teacher and one time my teacher 10 me after I played entire pieces of music wrong in front of her colleagues. I was so 11 that I could hardly say anything. But her 12helped ease my shame. These memories13good or bad, never caused my14 for playing the piano again.

    This thought then led me to think that 15 is like music, and that we all try to play different 16 in the instrument of our life. Sometimes the pitch (音高) is17when we play it well, but sometimes we are out of tone. However, we all continue to create our own 18style of music. No matter what style our music is, it is 19 that we sing the songs of joy, quietness and love. Though I may never make it back to piano lessons, it doesn't 20 that I've stopped making music.

有关信息的传播与信号的应用下列叙述正确的是（　　）

在患急性肠炎时，要及时注射生理盐水；不慎受外伤以后，要用生理盐水清洗伤口；在高温作业时，要喝淡盐水。以上三种做法的主要原因依次是(　　)
①消毒　②维持水分代谢的平衡　③维持无机盐代谢的平衡　④降温　⑤是细胞的等渗溶液并有清洁作用

小龙背着质量为25kg的实验器材从实验楼的一楼上到三楼，又沿着走廊水平走了5m到达实验室．每层楼高3m，小龙对实验器材做功____ J．若在搬运实验器材的整个过程中小龙总共做功4500J，则小龙自身体重____ kg．（g=10N/kg）

    One October morning, I got off the all-night train in Mandalay, a city in Myanmar. A rough man came up and offered to show me around. The price he asked was less than I would pay for a bar of chocolate at home. So I climbed into his trishaw(三轮车).

    As he was showing me around, he told me how he had come to the city from his village. He'd earned a degree in mathematics. His dream was to be a teacher. But of course, life is hard here, and so for now, this was the only way he could make a living. Many nights, he told me, he actually slept in his trishaw so he could catch the first visitors off the all-night train.

    And very soon, we found that in certain ways, we had so much in common---we were both in our 20s, we were both fascinated by foreign cultures----that he invited me home.

    So we turned off the wide, crowded streets, and came to rough, wild alleyways(小巷). I really lost my sense of where I was, and realized that I could easily get cheated or something even worse.

    Finally, he stopped and led me into a hut. And then he reached under his bed. Something in me froze. I waited to see what he would pull out. And finally he took out a box. Inside it was every single letter he had ever received from visitors from abroad.

    So when we said goodbye that night, I realized he had also shown me the secret point of travel, which is to go inwardly(向内心)as well as outwardly to places you would never go otherwise, to go into uncertainty, even fear.

    At home, its dangerously easy to think we're on top of things. Out in the world, you are reminded every moment that you're not, and you can't get to the bottom of things, either.