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（1）上图中，切断a处的工具酶是____________ ，切断b处的酶是 ______。
（2）作为目的基因载体的细菌质粒往往要带有一个抗生素抗性基因，该抗性基因在基因工程中主要用于_____________________________________________________。
（3）苏云金芽孢杆菌的抗虫基因导入棉花细胞是否表达，最简便的检测方法是________________________________________________。
（4）苏云金芽孢杆菌的抗虫基因转到农作物体内后，也能产生伴孢晶体蛋白，说明___________________________。
（5）转基因工程改良动植物品种，最突出的优点是_____________________________ 。
（6）大面积种植抗虫棉对该地区生态平衡会造成怎样的影响？
①________________ _____________
②_____________________ _____。 查看习题详情和答案>>
阅读短文，根据要求完成下面各小题。
In the past twenty years, riding bicycles has become more and more popular among people of all ages. 83 Bicycles have long played an important part in the liyes of American young people. But today an even greater number of adults cycle along roadsides and bicycle paths. These new riders are often trying to become fit or lose weight. They have found that bicycling is a pleasant way to stay healthy
This is certainly good for health. But it has also brought some problems. With all these added people on the road, bicycle safety has become a matter of real importance.
Bicycle safety is mostly a matter of common sense. People should ride only on bicycle paths where they will not be badly hurt. There are also a number of rules that riders should follow, especially when riding on streets or highways. Bicyclists should never ride against the traffic,nor should they carry other people on their bicycles. They are also supposed to ride in single line on busy streets and to "walk bicycles across the busy intersections (交叉路口) . 84By following these rules, bicycle riders will not only stay healthy but also be safe.
In one recent year, the National Safety Council reported that 34 thousand bicycle riders were hurt in highway accidents. In that same year, another six hundred riders were killed. Since the introduction of crash helmets (头盔) in 1980, the number of injuries (伤者) and deaths from bicycling accidents had gone down. Today, more and more riders realize the dangers of bicycling. They are wearing helmets and paying closer attention to cycling rules.
A. 根据短文内容回答下列问题。
1.How many rules should the riders follow? Give one example.
_______________________________________________________________
2. According to the National Safety Council's report, what's the total number of injuries and deaths in one recent year?
________________________________________________________________
B. 将短文中划线部分译成汉语。
3._______________________________________________________________
4.________________________________________________________________
C. 请给短文拟一个适当的英文标题。
5.________________________________________
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一、制备K
s*5u二、提纯
方案1
方案2
主要试剂和产品的物理常数
| 名 称 | 相对分子质量 | 熔点或沸点（0C） | 水 | 醇 | 醚 |
| 水杨酸 | 138 | 158(熔点) | 微溶 | 易溶 | 易溶 |
| 醋酸酐 | 102 | 139.4(沸点) | 反应 | 可溶 | 易溶 |
| 乙酰水杨酸 | 180 | 135(熔点) | 微溶 | 可溶 | 微溶 |
（1）①合成阿斯匹林时，还会生成一些副产品，其中有一种是高分子，为了分离此物质，方案1中加入A物质为 ▲ 溶液。
②本方案抽滤后进行洗涤，其具体操作是 ▲ 。
（2）方案2为改进的提纯方法，称为重结晶提纯法。
①该方案中步骤1除了选用乙酸乙酯外，还可选择下列哪些
试剂 ▲ 。
A. 乙醇 B. 蒸馏水 C. 乙醚
②步骤2回流的装置如图所示，写出仪器a的名称 ▲ ，使用温度计的目的是 ▲ ，冷凝水的流向为 ▲ 。
③方案2所得产品的有机杂质要比方案1少的原因是 ▲ 。
（3）该学习小组在实验中原料用量：2.0g水杨酸、5.0ml醋酸酐（ρ＝1.08g·cm-3），
最终称量产品m="2.2g" ，则乙酰水杨酸的产率为 ▲ 。 查看习题详情和答案>>
In the past twenty years, riding bicycles has become more and more popular among people of all ages. 83 Bicycles have long played an important part in the liyes of American young people. But today an even greater number of adults cycle along roadsides and bicycle paths. These new riders are often trying to become fit or lose weight. They have found that bicycling is a pleasant way to stay healthy
This is certainly good for health. But it has also brought some problems. With all these added people on the road, bicycle safety has become a matter of real importance.
Bicycle safety is mostly a matter of common sense. People should ride only on bicycle paths where they will not be badly hurt. There are also a number of rules that riders should follow, especially when riding on streets or highways. Bicyclists should never ride against the traffic,nor should they carry other people on their bicycles. They are also supposed to ride in single line on busy streets and to "walk bicycles across the busy intersections (交叉路口) . 84By following these rules, bicycle riders will not only stay healthy but also be safe.
In one recent year, the National Safety Council reported that 34 thousand bicycle riders were hurt in highway accidents. In that same year, another six hundred riders were killed. Since the introduction of crash helmets (头盔) in 1980, the number of injuries (伤者) and deaths from bicycling accidents had gone down. Today, more and more riders realize the dangers of bicycling. They are wearing helmets and paying closer attention to cycling rules.
A. 根据短文内容回答下列问题。
【小题1】How many rules should the riders follow? Give one example.
_______________________________________________________________
【小题2】 According to the National Safety Council's report, what's the total number of injuries and deaths in one recent year?
________________________________________________________________
B. 将短文中划线部分译成汉语。
【小题3】_______________________________________________________________
【小题4】________________________________________________________________
C. 请给短文拟一个适当的英文标题。
【小题5】________________________________________ 查看习题详情和答案>>
（1）上图中，切断a处的工具酶是____________ ，切断b处的酶是 ______。
（2）作为目的基因载体的细菌质粒往往要带有一个抗生素抗性基因，该抗性基因在基因工程中主要用于_____________________________________________________。
（3）苏云金芽孢杆菌的抗虫基因导入棉花细胞是否表达，最简便的检测方法是________________________________________________。
（4）苏云金芽孢杆菌的抗虫基因转到农作物体内后，也能产生伴孢晶体蛋白，说明___________________________。
（5）转基因工程改良动植物品种，最突出的优点是_____________________________ 。
（6）大面积种植抗虫棉对该地区生态平衡会造成怎样的影响？
①________________ _____________
②_____________________ _____。 查看习题详情和答案>>