已知向量，动点到定直线的距离等于，并且满足，其中为坐标原点，为非负实数. （1）求动点的轨迹方程； （2）若将曲线向左平移一个单位，得曲线，
向某AgNO3溶液中加入一定量Zn、Cu混合粉末，充分反应后过滤，得到滤渣A和蓝色滤液B；再向B中加入一定量Zn粉充分反应后过滤，得到滤渣C和滤液D。取滤
During the Second World War ,the story happened. An old man lived in a small town of Germany. He had three sons and they all worked in the same factory where he had worked. After the war had begun,
--Look! It ________ be the new woman manager． -It ________ be her．She has just left for Shanghai． A．can; mustn't B．must; can't C．must; mustn't
The boy is only five years old, but he is quite used the telephone. A. to answer B. to answering C. of answering D. by answering
___________ a fine day, Shenzhou VI will be launched on time according to its planned time. A. Being B. It being C. To be D. It is
在真空密闭容器中盛有1 mol PCl5加热到200℃时发生的如下反应： PCl5（气）PCl3（气） +Cl2（气），反应达平衡后，PCl5所占体积分数为M%。若在同一温度和
I was giving a talk to a large group of people，the same talk I to half a dozen other groups. A.was giving B.am giving C.had
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