问题
选择题
在FeCl3、CuCl2、FeCl2的混合溶液中，Fe3+、Cu2+、Fe2+的物质的量浓度之比为4︰2︰1，现加入适量的铁粉，使溶液中的三种离子的物质的量浓度之比为1︰3︰9，则投入的铁粉与原溶液中Cu2+的物质的量之比为[ ]
A．5︰4
B．4︰5
C．3︰5
D．5︰6
答案
答案：D
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在FeCl3、CuCl2、FeCl2的混合溶液中，Fe3+、Cu2+、Fe2+的物质的量浓度之比为4︰2︰1，现加入适量的铁粉，使溶液中的三种离子的物质的量浓度之比为1︰3︰9，则投入的铁粉与原溶液中Cu2+的物质的量之比为[ ]
A．5︰4
B．4︰5
C．3︰5
D．5︰6
答案：D
Choose the words or expressions and complete the passage（选择最恰当的单词或词语完成短文)（12分） The book that can’t wait One problem a lot of people have with books is that they buy them and then never start reading them. To 【1】, a foreign publisher called Eterna Cadencia came up with a very clever idea: it printed the words of the books in disappearing ink: the text of the book vanishes(消失) two months after the special package of the book is opened, so that encouraging buyers to start reading it 【2】 it goes away. They call this “the book that can’t wait.” According to a video presented with the story, the book was 【3】 . The publisher sold out the whole first edition(版) at a bookstore the day it was printed, and received “thousands of requests” for more copies of the book. It also got a lot of news reports. As a result, the publisher is planning to publish 【4】 kinds of books in disappearing ink. In some ways, the idea is pretty clever.【5】, we still have some suggestions: First, the book should start the vanishing process after the reader first opens the book. If the vanishing ink books become very popular in the future, readers will need to read them one at a time. They don’t want their books to vanish before they read the first page. Second, the vanished book should find a 【6】 use. Maybe they can be recycled, or maybe we can use them as notebooks. It would be a more environmentally friendly way to do this.
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