①f（x）= $\sqrt{-2x^3}$ 与g（x）=x $\sqrt{-2x}$

②f（x）=|x|与g（x）= $\sqrt[3]{x^3}$

③f（x）=x⁰与g（x）= $\frac{1}{x^0}$

④f（x）=x²﹣2x﹣1与g（t）=t²﹣2t﹣1．

下列有关滴定操作的顺序正确的是（　　）

①用标准溶液润洗滴定管   

②往滴定管内注入标准溶液      

③检查滴定管是否漏水

④滴定                   

⑤洗涤．

眼睛、血液、唾液腺依次属于（　　）

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   Thank you for joining CCTV’s around the World show. Today we are in Egypt(埃及). It’s beautiful sunny day! There are many people here on  .Some are taking photos. Others are riding camels （ 骆驼 ）.The Egyptians (埃及人)are wearing a kind of scarf on their heads. They look cool! They wear them because it is so hot . This is a very interesting place . I'm looking at the five thousand years of history .