下列反应的离子方程式书写正确的是 A.铝与氢氧化钠溶液反应: 2Al+ 2OH—

题型:选择题

问题:

下列反应的离子方程式书写正确的是

A.铝与氢氧化钠溶液反应: 2Al+ 2OH=2AlO2+H2

B.碳酸钙和醋酸反应:2H+ +Ca CO3= Ca2++CO2↑ + H2O

C.铜和稀硝酸反应:Cu + 2H= Cu2++ H2

D.SO2通入溴水中:SO2+Br2+2H2O=4H++SO42—+2Br

考点:离子方程式
题型:选择题

总蒽醌中分出含一个β-OH的蒽醌,可选用()

A.5%Na2CO3溶液

B.5%NaHCO3溶液

C.0.5%NaOH溶液

D.热5%NaHCO3溶液

E.4%NaOH溶液

题型:选择题

拟制血亲

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There are several ways you can find out about the countries and places you wish to visit. You can talk to friends who have travelled to the places. Or you can go and see a colour film. Or you can read travel books.

It would seem that there are three kinds of travel books. The first are those that give a personal, subjective(主观的) account of travels which the author has actually made himself. if they are informative and have a good index(索引), then they can be useful to you when you are planning your travels. The second kind are those books whose purpose is to give a purely objective(客观的) description of things to be done and seen. If a well-read, cultured person has written such a book, then it is even more useful. It can be sorted as a selected guide book. The third kind are those books which are called “a guide” to some place or other. If they are good, they will, in addition to their factual information, give an analysis or an explanation. Like the first kind they can be inspiring and interesting. But their basic purpose is to help the reader who wishes to plan in the most practical way.

Whatever kind of travel book you choose you must make sure that it does not describe everything as “wonderful”, “excellent” or “magical”. You must also note its date of publication because travel is a very practical affair and many things change quickly in the twenty-first century. Finally, you should make sure that the contents are well presented and easy to find.

小题1:This passage is about _______.

A.how to travel

B.how to buy travel books

C.how to read a travel book

D.travel books小题2:The following travel books may be of use when you plan your travels except _______.

A.the book written by some people who have had the same travel experience themselves

B.the book which tells you what is worth doing and seeing based on the facts

C.the book in which a lot of big adjectives are used to draw your attention

D.the book which offers you a lot of useful information like a tour guide小题3: The date of the publication must be noticed because _______.

A.the world is changing and so are the places you are going to visit

B.the price of the book is always changing

C.the author of the book may be different

D.the contents of the book are always the same

题型:选择题

机动车因故障在下坡道停车,要使用驻车制动器后将变速杆挂入空挡。

题型:选择题

在VB6.0中,用于设置ADO结果集的内容,这个内容可以来自一张表,也可以来自一个查询语句,还可以来自一个存储过程的执行结果的属性是()。

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