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问题 选择题

除去粗盐中的Ca2+、Mg2+、SO42-及泥沙，可将粗盐溶于水，然后进行下 * *  项操作：①过滤；②加过量的氢氧化钠溶液；③加适量的盐酸；④加过量的碳酸钠溶液； ⑤加过量的氯化钡溶液．下列正确的操作顺序是（　　）

A．①④②⑤③

B．⑤②①④③

C．④①②⑤③

D．②⑤④①③

答案

答案：D

单项选择题

胎产式是指：

A．35cm，1000g
B．45cm，2500g
C．16cm，110g
D．25cm，320g
E．50cm，3400g胎儿身长，体重
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改错题

Yesterday I go shopping in the supermarket. As I was looking at the goods I noticed a old man who seemed to be following me wherever I went. As I moved, there he was, smiled at me. I wondered that if I had done something wrong. But I didn't think I had. So I believed there must be anything wrong with him. I became a bit scared. At the food section I selecting the chicken when I felt a tap on the shoulders. Turn around, I saw that it was the same man. "Lady," he final said, "youhave my shopping basket." At that moment I realized I misunderstood him, so I said sorry for him at once.
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