将奇数按下列方式分组：（1），（3，5），（7，9，11），（13，15，17，19），…．

地球自转的方向是　____ 　（北极上空往下看是____ 针），自转一周的时间约为____ ，也就是　____ ．

I'm David．When I was 13,my parents decided that I should go to England to improve my English．I had never been to other countries before，so I felt a little worried．My parents prepared everything for my journey．My plane was due(预期)to leave at 9：30 a．m．and arrive in two hours．I phoned the English family who I would stay with and they told me they would wait for me at the airport(机场)．

Unluckily my plane to London was delayed (延误)．I tried to phone the English family again but I couldn't speak to them because they had already left home for the airport．

When I arrived in London．it was already 1：30p.m．I went to get my luggage(行李)but I couldn't find it．I became very worried．Luckily, the airport staff(工作人员)was very helpful and efficient．I didn't wait long-they found it 10 minutes later．

My English family were still waiting for me! I was so happy! Then my new life in London began．My English family were quite kind．I learned a lot of English because I spent most of the day talking in English．I played computer games with the little boy in my English family．I also taught him how to play chess．Sometimes I told him stories I learned from my family．

I missed my family during my stay in London．but I also feIt sad when my stay there came to an end．My English family held a party for me．I enjoyed it very much．I’ll never forget that summer in London! It is one of the most wonderful experiences I've ever had．

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                                                                                         “情绪污染”也是病
      所谓“情绪污染”，是指一个人的坏心情影响了几个人的好心情。其实，家庭中的“情绪污染”尤其值得注意。其明显特征，一是“患病的多”：因孩子生气，因家务生气，因性格不合生气，因在外面不顺心生气，回家拿老婆孩子生气等等。总之，鸡毛蒜皮的小事都可以生气。有人研究认为，家庭气氛如果长期压抑、沉闷，很容易使人神经系统紊乱，免疫能力下降，患病机率升高。正所谓“情绪致病”。现代医学研究证明，凡患情感失调的人，发病的风险是正常人的2倍。因而发出了“生气等于自杀”的警告。
      防止“情绪污染”，主要还是加强品格和心情修养。人心情愉悦，就能分泌更多的内啡肽，使人精神快乐，健康长寿。反之，则会减少这种物质的分泌，使人抑郁寡欢，加速老化。某刊曾登载如下相处金言：“为小事争吵是愚蠢，为大事争吵是无能。做你该干的事，不做无谓的精神消耗。”其次，要善于克制与忍让。不少大腕、政治家都不断警示自己要“制怒”，要“骤然临之而不惊，无故加之而不怒”。
      作为普通百姓，更应该“有话好好说”，有事商量着办，切不可动辄争吵、斗气、自家相残。再次，要审视自己，多加交流。人无完人，谁都有毛病。家庭成员之间特别是夫妻之间，多交流，多沟通，及时了解对方的意见、看法和心理需求。寻找共同点，扩大共同点，共同构建欢愉和谐的家庭气氛。
      此外，还有扩大宽容，多点幽默。所谓宽容，即互谅互让。幽默不仅体现宽容，而且富有趣味和启示，能调节情绪，宽松气氛，使人步入和谐，感受更为从容乐观的思想境界。有所悟之人曾造出如下箴言：“要努力把自己培养成一个性情乐观的人，记住．自己所能干的就是给身边的人带来轻松和愉快。”