题目

甲、乙两物体在同一直线上，同时由一位置向同一方向运动，其速度-时间图像如图所示，下列说法正确的是    （     ）A．甲作匀加速直线运动，乙作匀速直线运动；B．开始阶段乙跑在甲的前面，20s后乙落在甲的后面C．20s末乙追上甲，且甲、乙速率相等D．40s末乙追上甲  答案：D解析:略 There are many things you can do to improve your memory. Among them are many kinds of useful ways as well as taking special care of your health.It is important that you make yourself excited to make your memory more active. You can do this by doing some new activities and by changing your daily habits. Learning a new skill helps your brain (大脑) to develop. When trying to remember something, you should pay special attention to the most important things about it. Do not allow other thoughts to enter your mind because this will reduce your chances of making right memories.An excellent way to help memory is to connect information with pictures. Try to see the pictures in your mind. Taking notes and keeping a diary will also be helpful.Healthy food and plenty of vitamins are necessary for your memory to work well. Drinking a lot of water also helps keep your memory. You must allow your brain to have enough sleep and rest. When you are asleep, your brain stores memory. Not enough sleep can cause problems with storing information. And being tired will also stop you from being able to think clearly and well.In order to keep your mind on your work, you must be free from worry. Generally keeping fit and normal health checks are both important as well—not just for improving your memory.TitleHow to【1】 Your Memory Main 【2】Taking 【3】 care of your health Making yourself【4】 to make your memory more active by 【5】 part in some new activities and changing your daily habits Paying attention to the most 【6】 things, in order to add to your chances to make right memories Connecting information with 【7】Taking notes and keeping 【8】Other waysEating healthy food and taking plenty of vitamins【9】 a lot of waterHaving【10】 sleep and rest