题目

（2010嘉兴）为了寻找“手臂上的杠杆”做了如下实验，小明右手拿着书，先让手下垂，左手掌贴着右上臂的前部（肱二头肌），将右下臂慢慢抬起到水平位置，他感觉到右上臂的肱二头肌越来越紧张。请你结合如图所示，利用杠杆原理解释产生这一现象的主要原因    。  答案：由于阻力臂越来越大，动力就越来越大。 只要能答出“阻力臂越来越大”即可。根据短文内容及首字母提示，填写所缺单词（每空一词，计10分）Have you had a headache during a test? Have you ever been so worried about something t _1._ you have a headache or even can’t sleep at night? If s__2.__, then you know what stress is. Stress is what you f_3.__ when you are worried about something. This worry in your mind can make your body feel bad. You may feel angry, sad, scared, or afraid. All of them can give you a stomach or a headache.However, there are different kinds of stress. Some kinds of stress are good and o_4.__ are bad. Good stress might happen when you are called to answer questions in class. This kind of stress can help you get things better done. For e__5.__, you may do a better job on your test if the stress pushes you to p__6._ better before the test.On the other hand, bad stress can happen if the stress l__7.__ too long. You may not feel well if your parents are fighting, if a family m_8.__ is sick, and if you are having problems at school, or anything else makes you unhappy every day. That kind of stress isn’t going to help you. And it can actually make you sick.The best way to fight stress is to have a balanced life. Make s__9._ you keep your SELF in mind: Sleep, Exercise, Leisure(休闲) and Food. If you get e__10.__ sleep and eat properly, and if you exercise and leave time for fun, you’ll probably feel less stressed.