题目

假设小明手上此刻有200个细菌，细菌的繁殖速度按每30分钟繁殖一代计算，在没有洗手的情况下，四小时后他手上的细菌数目是    A．51200     B．1600     C．3200     D．256000 答案：A10．Autumn was coming to an end．All the insects and animals were working hard to store food for winter，except the grasshopper（蚱蜢），who spent his days （71）jumping（jump） from leaf to leaf．One day，an ant happened to pass by．She （72）was pulling（pull） a heavy grain of rice．"Could you give me （73）ahand．Mr．Grasshopper？"asked the ant．"My anthill is just a few trees away，but this is so heavy．""You come and play with me for some time，and then I shall gladly help you．Autumn is so beautiful．You should enjoy it，"the grasshopper replied．"No，sir．You must also start preparing for the winter （74）ifyou want to have enough to eat，"the ant said （75）seriously（serious）．"Nothing doing．Right now it is time （76）to have（have） fun，"the silly grasshopper replied．Hearing this，the ant shook her head and went on．Winter came．The ant stayed （77）inher warm anthill and enjoyed her food，（78）whilethe grasshopper had to suffer from cold and hunger．He went out to hunt for food when it was （79）warmer（warm） than usual，but he could hardly find any food and soon became weak with hunger．"Oh，why did I waste my （80）days（day） playing？I should have listened to the ant，"he thought with regret．