阅读理解

    Hummingbirds(蜂鸟) are one of nature's most energetic fliers and the only birds to hover(盘旋) in the air by relying on their strength alone.

    Now scientists have found that it is the ratio(比值) of the bird's wing length to its width that makes them so efficient. The discovery is helping experts compete with 42 million years of natural selection to build helicopters that are increasingly efficient.

    David Lentink, an assistant professor at Stanford University in California, tested wings from 12 different species of hummingbirds, which he sourced from museums. He placed them on a machine used to test the aerodynamics(气力学) of the helicopter blades(桨叶). Professor Lentink's team used the same machine to test the blades from an advanced micro-helicopter used by the UK's army. They found that the micro-helicopter's blades are as efficient at hovering as the average hummingbirds.

    But while the micro-helicopter's blades kept pace with the average hummingbird wings, they could not keep up with the most efficient hummingbird's wing. The wings of Anna's hummingbird were found to be about 27 percent more efficient than the man-made micro- helicopter's blades.

    While Professor Lentink wasn't surprised at nature's superiority, he said that helicopter blades have come a long way. “The technology is at the level of an average hummingbird,” he said. “A helicopter is really the most efficient hovering device that we can build. The best hummingbirds are still better, but I think it's amazing that we're getting closer. It's not easy to match their performance, but if we build better wings with better shapes, we might match hummingbirds.”

    Professor Lentink said that we don't know how hummingbirds maintain their flight in a strong wind, how they navigate(确定方向) through branches, or how they change direction so quickly. He thinks that great steps could be made by studying wing aspect ratios-the ratio of wing length to wing width. Understanding these abilities and characteristics could be a benefit for robotics and will be the focus of future experiments.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内.

假设你叫李华，你的英国笔友Jack不久前去美国留学，他给你写信说很不适应那里的生活.请你根据以下提示用英语给他写封回信，鼓励他勇敢面对.

要求：1）了解当地生活习惯，尊重当地风俗；

       2）与美国学生多交流；

       3）多参加户外活动；

       4）注意与人交流的礼仪.

注意：1）内容应包括以上所有信息，要有适当发挥.

2）词数：100左右.信的开头和结尾已经写好，不计入总词数.

       3）参考词汇：课外活动：activities after class

Dear Jack,

I'm really glad to hear from you and know how you are getting along.

Yours,

Li Hua

假设你叫李华，你的英国笔友Jack不久前去美国留学，他给你写信说很不适应那里的生活.请你根据以下提示用英语给他写封回信，鼓励他勇敢面对.

要求：1）了解当地生活习惯，尊重当地风俗；

       2）与美国学生多交流；

       3）多参加户外活动；

       4）注意与人交流的礼仪.

注意：1）内容应包括以上所有信息，要有适当发挥.

2）词数：100左右.信的开头和结尾已经写好，不计入总词数.

       3）参考词汇：课外活动：activities after class

Dear Jack,

I'm really glad to hear from you and know how you are getting along.

Yours,

Li Hua

阅读下面短文，从短文后各题所给四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑.

    When I spent the summer with my Grandpa in Warwick, he sent me to Miss Bee's store. 1 the counter was Miss Bee. A pair of glasses teetered(摇摇欲坠) on the 2 of her nose, gray hair was 3 on her head.

    “Excuse me. I need to get these.” I said. “So?” She pushed her glasses 4 her nose. “There's no one here except you and me and I'm not your 5. Go get them. If you're lucky you'll finish shopping by sundown.” Sundown was five hours 6. I wasn't sure l would 7 it.

    How could I hope to find anything on the packed, jumbled(乱堆的) shelves around me?

    I visited Miss Bee several times a week. Sometimes she short-charged me. Other times she overcharged. 8 she sold me a/an 9 newspaper instead of one that was current. Going to the store was more like going into battle.

    “That bread is only twenty-nine cents!” I corrected her one afternoon. I had watched the numbers change on the cash register(收款机) closely, and Miss Bee had added 35 cents. She didn't seem 10 that I had caught her 11. She just looked at me and 12 the price.

    All summer I learned the hard way to 13 my list. But she still found ways to 14. me into making mistakes. No sooner had I memorized the items' location on the shelf than Miss Bee 15 the shelves and made me hunt for 16 all over again. The morning I was to 17 to Brooklyn, I stopped in to get a packet of gum.

    “All right,” she said. “What did you learn this summer?” She was mean! I pressed my lips together. To my 18, Miss Bee laughed. “I know what you think of me,” she said. “ but when you get older you'll be glad our paths 19!” Glad I met Miss Bee? The idea was 20.

    Now I grow up and I finally understand I really learned a lot from Miss Bee.