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【简答题】
2012年4月15日央视《每周质量报告》报道的“毒胶囊”中使用的明胶含有重铬酸钾（K 2 Cr 2 O 7 ），重铬酸钾是一种有毒且有致癌性的强氧化剂，其中的铬（Cr）是有毒的重金属元素．请回答： （1）K 2 Cr 2 O 7 中铬元素的化合价是______价． （2）取一铬的薄片，用砂纸打磨光亮，放入稀硫酸中，发生了类似稀硫酸的反应，可观察到铬片表面缓慢地产生气泡，溶液变蓝色；查阅资料可知，铬与稀硫酸反应生成硫酸亚铬（CrSO 4 ），硫酸亚铬溶于水呈蓝色．请写出将光亮的铬片放入稀硫酸中所发生反应的化学方程式：______．
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【单选题】What is the term that indicates his literary idea?
A.
The tip of iceberg
B.
Narrative perspective
C.
Flat character and round character
D.
Sequence of narration
【单选题】What could be Americans’ attitude towards paying without tip?( )
A.
Americans never pay the tip.
B.
Paying without tip may irritate or upset some Americans.
C.
Tip is not a must thing in America.
D.
Americans pay the same amount of tip for everything. 答案：B
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【单选题】Tip 3 and Tip 4 give you some advice on what you should do when you are ______.A.
A.
60. Tip 3 and Tip 4 give you some advice on what you should do when you are ______. A. inside a building
B.
outside a building
C.
in your house
D.
in a store
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