融雪剂中的一种为氯盐融雪剂,其成分中包括氯化钠、氯化钙、氯化镁和氯化钾,俗称“化

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问题:

融雪剂中的一种为氯盐融雪剂,其成分中包括氯化钠、氯化钙、氯化镁和氯化钾,俗称“化冰盐”.某课外小组将等质量的氯化钙与氯化镁混合,该混合物中氯元素的质量分数为(列出表示式即可)______.

考点:物质组成元素的质量分数
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一般常用的非金属材料有()、()、()等。

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急性早幼粒细胞白血病(M型)的遗传基因标志是()

A.PML-RARa融合基因

B.DEK-CAN融合基因

C.AML1-MTG8融合基因

D.Ph染色体

E.EA-PBX融合基因

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阅读理解。

    Once Lu Xun spoke to the young men about the study of foreign languages. He said: "You must not give

up studying foreign languages for even a day. To master a language, words and grammatical rules are not

enough. You must do a lot of reading. Take a book and force yourself to read it. At the same time, turn to

dictionaries and memorize grammatical rules. After reading a book, it's only natural that you won't understand

it all. Never mind. Put it aside, and start another one. In a few months or half a year, go over the first book

again; you are sure to understand much more than before... Young people have good memories. If you

memorize a few words every day and keep on reading all the time, in four or five years, you will certainly be

able to read works in the foreign language."

1. In order to master a foreign language, words and grammatical rules are ______. [ ]

A. the most important thing

B. necessary

C. all we should remember

D. almost enough

2. If you can't understand it all when you read a book, you should ______.[ ]

A. start with its beginning again

B. look up the new words in your dictionary and recite them

C. start another one and go over the first one later

D. stop to learn the grammatical rules in the book

3. What's Lu Xun's advice on how to learn foreign languages? [ ]

A. Memorize as many new words as you can when you are young.

B. Keep on reading all the time.

C. Force yourself to read a book until you can understand it all.

D. Never give up reading and try to remember new words in reading books.

4. This passage mainly tells us how to ______.[ ]

A. do our reading

B. turn to dictionaries

C. memorize new words

D. use grammatical rules

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已知某烧结厂熔剂破碎筛分过程中测得筛下皮带小于3mm的石灰石量为17.5kg/m,带速1.32m/s;筛上皮带小于3mm的石灰石量为2.5kg/m,带速1.67m/s,试计算其筛分效率?

题型:问答题

列车施行制动后,不再进行缓解,根据列车减速情况进行追加减压,即可使列车停于预定地点,叫作()

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