题目

鉴别一个细胞是动物细胞还是植物细胞，应检查它有无A细胞核    B细胞质   C细胞膜   D细胞壁 答案：D解析:略 What a cold winter! How wonderful it would be if there were a fire! Fire keeps us warm, but fire is very dangerous, and can kill us. November 9 is National Fire Safety Day. It's a time for us to learn a lot more about fire, especially what to do if we are caught in a fire. 　 Call 119 　 Never try to put out a fire by yourself, even if it is a very small one. Get help from your parents or call 119. Tell 119 where you are and what is on fire. Listen to 119's instructions. 　 Keep down close to the floor 　 If there is a lot of smoke in your room, keep down close to the floor. There is less smoke down there, so it's easier to breathe(呼吸) and see where you are going. If you don't, the smoke may kill you before the fire does. 　 Don't use the elevator 　 Never use the elevator(电梯) during a fire. Always use the stairs. An elevator may stop at the floor where the fire is burning. It may also go wrong and keep you inside. 　 Don't go back 　 Never go back into a burning building, even if you have left your pet or favorite toy inside. Do not go back for it. Don't worry about your pets. Animals have a very good sense of smell(嗅觉). They often get out of the building before people. (　 ) 41. National Fire Safety Day is on November 9. (　 ) 42. If you smell smoke or see a fire, you should call 120 first. (　 ) 43. If there is a lot of smoke or a fire, the fire may kill you before the smoke. ( 　) 44.You mustn't use stairs during a fire because it may catch fire as well. (　 ) 45.Animals have a good sense of smell.