—They moved here soon after their son was born.

在△ABC中，点D、E分别是边AB、AC上的点，且有$\frac{AD}{DB}$=$\frac{AE}{EC}$=$\frac{1}{2}$，BC=18，那么DE的值为（　　）

以下是制定并研究设计的“试管牛”工厂化生产技术流程，其中正确的顺序应是(　　)。
①卵母细胞的采集和培养　②精子的采集和获能　③画出“试管牛”工厂化生产技术流程图　④受精　⑤胚胎的早期培养

    Buttons are found on all sorts of clothing. They are usually small and round and made of metal or plastic. They fasten, or connect, one piece of clothing to another. They make sure your clothes don't fall off. When we are speaking or writing m English, buttons can be just as useful.

    Men or women often wear button-down clothes to the office. Button-down as an adjective means to be conservative（保守的）or traditional. People who are described as buttoned-down stay close as possible to the normal way of dressing and behaving. They don't wear crazy clothing or do unusual things. People and events can both be described as buttoned-down.

    If someone is buttoned-up, he or she seems very business-like. In personal relationships, a buttoned-up person is cold and standoffish, meaning they physically and emotionally keep away from others. Buttoned-up people are not warm or friendly. And they do not share their inner thoughts and feelings with others.

    In the expression “button up”, button is a verb. It means to stop talking. Now, let's say you find yourself buttonholed in a conversation at a party. The person just keeps talking and talking and talking! Finally, you can't take it any longer. You tell the person to button it! This is a direct, but unacceptable way of saying “stop talking”. Button you lip is another equally rude but effective to stop a person who talks too much.

    Another kind of difficult person is someone who pushes your buttons. To push someone's buttons means to know exactly how to get that person angry or upset. People who like to push other people s buttons usually do it for selfish reasons. First they find a person's weak point. Then they use it to upset him.