题目

在国际单位制中，力学的基本单位是：（    ）  A．N、m、s           B．kg、m、s  C．N、kg、s          D．N、kg、m  答案：B 解析:略 Worried about sports injuries (伤害)? The best way to do with sports injuries is to prevent them. Sports injuries are injuries that happen while doing sports. You may think of your back or your arms and legs as the only places where you could get hurt while playing, but you can get a sports injury anywhere on your body. Head and neck injuries are among the most dangerous. You can hurt your neck in sports like mountain climbing, skydiving, horseback riding, diving, or boxing. If the injury is serious and there is a chance that the neck might be injured, it’s very important to keep the injured person still with the head held straight while someone calls for emergency medical help (急救). If the person is lying on the ground, do not try to move him or her. Never try to move someone who may have a neck injury – a wrong treatment could even result in death. Always remember that an injury left untreated will probably get worse over time. Yet, it’s not always necessary to see a doctor right away if your pain is slight (轻微的). The most important thing to do when you feel you are injured is to stop doing whatever sport has caused the injury right away and go to see a doctor. For more serious or complicated (复杂的) injuries, it may be best to see a doctor. If your doctor has asked you to stop playing, your number-one question is probably “When can I play sports again?” Make sure you discuss this with your doctor. Always wear helmets (头盔) for contact (接触) sports and when doing activities like biking and roller-skating to prevent head injuries. When you return to play, you might need some new protective equipments (装备) that help protect your body part from possible reinjury. To help prevent reinjury, be sure to warm up before practice and games. Remember to take it slow when you first get back into your sport. So, play, but play safe. Try to learn from your experience and do the things that can help you keep away from getting hurt. 1. __________is a contact sport.   A. Volleyball                                     B. Tennis   C. Basketball                                    D. Golf 2. When a person falls off a horseback and can’t move, we should not __________.   A. take him to a safer place B. leave him where he is   C. keep his head straight D. call for emergency medical help 3. Before taking part in the relay race, we have to __________.   A. prepare useful equipments B. stand there waiting   C. make sure we have no injury          D. get ourselves ready 4. From the passage we learn that ___________.   A. we should go to see a doctor right away when we feel injured   B. we can return to sports as soon as we get medical treatment   C. stopping whatever sport has caused injuries is necessary       D. using protective equipments keeps you away from injuries