设NA为阿伏加德罗常数,下列叙述中不正确的是 A.pH=1的甲酸溶液中,HCOO

题型:选择题

问题:

NA为阿伏加德罗常数,下列叙述中不正确的是

A.pH=1的甲酸溶液中,HCOO和H+数目之和为0.1 NA

B.标准状况下,3.36L乙烯中含有的极性键数为0.6 NA

C.1 mol甲基(-CH3)所含电子数9NA

D.1mol油酸含有的双键数目约为6.02×1023

考点:物质的量
题型:选择题

在现代农业中提高农业产出的重要手段是(    )

A.农业机械的投入

B.科技投入

C.资金的投入

D.化肥、农药的投入

题型:选择题


Directions: There are 4 passages in this part. Each of the passages is followed by 5 questions or unfinished statements. For each of them there are 4 choices marked A, B, C and D. Choose the best one.
Passage One

American consumers like convenience very much. During the last 50 years, there has been a dramatic increase in such labor-saving devices as automatic washing machines, clothes dryers, dishwashers, food processors, microwave ovens, garbage disposals and power lawn mowers. Today, all of these and many more, are found in a typical suburban home. These labor-saving devices are designed to reduce the time spent on housework. However, the time that Americans save is quickly spent on other activities.
The American desire for convenience also created the concept of fast-food restaurants, found in every city and almost every small town in the United States, and now exported all over the world. These fast-food restaurants, such as McDonald’s and KFC, serve sandwiches, salads, fried chicken, seafood, and other food to hurried customers in five minutes or less, often at a drive-up window. There are also a wide variety of restaurants that will deliver Chinese food, pizza, and other dishes to people’s homes in about a half-hour. In many areas there are "take-out taxis" that will deliver food from the menus of 20 or 30 different restaurants for a small charge. For those who prefer to prepare their food at home, American grocery stores are full of convenience foods that are packaged and ready to cook or even precooked.
Like microwave ovens and dishwashers, fast-food and take-out restaurants are convenient because they save the American consumer time that would otherwise be spent fixing meals or cleaning up. More than half of all the women in the United States are currently employed. This includes mothers with children under the age of 18. More than half the women with little children under the age of six hold jobs. Sixty-eight percent of the women who have school-age children are employed. Families with working mothers need all the time-savers they can get.
Thus, the conveniences that Americans desire reflect not so much a leisurely lifestyle as a busy lifestyle in which even minutes of time are too valuable to be wasted. Alexis de Tocqueville was one of the first to see in this a curious paradox (自相矛盾) in the American character. He observed that Americans were so busy working to acquire comforts and conveniences that they were unable to relax and to enjoy leisure time when they had it. Today, many Americans have what one medical doctor has called "the hurry sickness".

"The curious paradox in the American character" (Last Para. ) means that ______.

A.Americans were so busy working to acquire comforts and conveniences that they were unable to relax and to enjoy leisure time when they had it

B.Americans love comforts and conveniences very much, yet they don’t know how to get them

C.Americans value time very much, yet they are too wasteful of material things

D.Americans know it’s unhealthy to eat fast food, but they just can’t resist it

题型:选择题

受理传真电报应填写传送方向单,对()编写电报号码、页数、分页数。

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对术后病人的一般护理要点有哪些?

题型:选择题

短路的概念?

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