控制动物行为的遗传物质贮存于细胞结构中的（　　）

    I don't like to stay at home during holidays. Last summer, my family took a 1to Hong Kong. It 2an interesting trip.

    We went there by plane, because we wanted to get there quickly. We3 there at about eleven o'clock and we had lunch there. We ate the seafood. It was delicious. The weather was sunny and 4 so we swam in the sea. There were 5people on the beach.

    Disneyland is the place that I like best there, so we 6visited the Disneyland. It is a 7place. We stayed in Hong Kong 8a week. We took many photos and bought lots of souvenirs. And then, we went home9.We just10a good time.

    I enjoyed the trip. It was really a fantastic trip.

如图，AB是⊙O的直径，点D在AB的延长线上，点C在⊙O上，CA=CD，∠CDA=30°．试判断直线CD与⊙O的位置关系，并说明理由.

下列变化过程不属于金属冶炼的是（　　）