射频识别（RFID）是物联网的关键技术。RFID标签又称电子标签，关于电子标签与条形码（barcode）标签的叙述，（）是正确的。
A.电子标签建置成本低，多个标签可被同时读取
B.条形码标签容量小，但难以被复制
C.电子标签通信距离短，但对环境变化有较高的忍受能力
D.电子标签容量大，可同时读取多个标签并且难以被复制
参考答案：D
解析：
射频识别标签，又称为射频标签、电子标签，主要由存有识别代码的大规模集成电路芯片和收发天线构成，目前主要为无源式，使用时的电能取自天线接收到的无线电波能量。射频识别读写设备与相应的信息服务系统如进存销系统进行联网。
将射频识别技术与条码（Barcode）技术相互比较，射频类别拥有许多优点，如可容纳较多容量，通信距离长，难以复制，对环境变化有较高的忍受能力，可同时读取多个标签。
射频识别技术相对也有缺点，就是建置成本较高，不过目前透过该技术的大量使用，生产成本就可大幅降低。
| 任务型读写。 阅读下面短文，根据所读内容在表格中的空白处填入恰当的单词。 注意：每个空格只填一个单词。 | ||||||||
| One reason Americans eat so many calories is that we tend to eat large portions (分量). Studies find that hamburgers and fries are generally offered in serving sizes two to five times larger than the appropriate meal size. Researchers find we usually clean our plates no matter how high they're piled, even if we already feel satisfied. See the suggestions below to further master the fine art of sizing up 估量) your snacks and suppers. Extremely large portions are one possible reason Americans continue getting fatter even as the percentage of our total calories from fat has gone down in recent years. Fortunately, portions are relatively simple to control because it's easier to count cookies than calories or grams of fat. Pre-picture portions. Use familiar objects to picture how much you should eat of a food before you pick up your fork or spoon. For example, a half cup of low-fat granola is about the size of your fist. A half cup of low-fat ice cream equals half an orange. Use a smaller dish. This tip might sound ridiculous, but it works. First and mostobvious is that you can't put as much food on, say, a salad plate. But psychologically, you're just not as prone to eat as heartily and quickly if your plate will be empty in 45 seconds. Have raw vegetables at every meal. Raw cucumbers, tomatoes, carrots, and peppers have few calories and lots of nutrients. A plate of them in the middle of the table almost always gets eaten up, cutting down appetite for the more calorie-dense meat. Start your meal with soup. Studies show that a bowl of soup at the start of the meal reduces overall meal consumption, since they are lowest in calories and highest in nutrients. Manage your fork. After every bite of food, put your fork down. Don't pick it up until you have thoroughly chewed and swallowed the previous bite. The goal is both to slow down your eating and to eat less. Remember: Your body needs 20 minutes of digestion before it sends signals to your brain that you are no longer hungry. | ||||||||
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