问题 阅读理解
根据短文内容,从下框的A-F选项中选出能概括每一段主题的最佳选项。选项中有一项为多余项。
A. Live below your means
B. Always stay positive
C. Educate yourself
D. Work towards a dream
E. Developing lasting personal relationships
F. Stay in shape
小题1:____________
We all want to buy that new piece of technology, treat ourselves to an expensive dinner, or take out a loan for the car we can't afford. It might feel great at the time but hasty(匆忙的)spending hurts a lot later on. Enjoy life's simple pleasures and save as much as you can. Expensive things don't create lasting happiness. Careful spending will bring you greater enjoyment in the long run.
小题2:_____________
To be happy we need continuous growth. The best way to grow is life-long education. This doesn't mean you need to pursue a doctorate or spend 2 hours reading every day. Self-education can be anything that takes you out of your comfort zone. The important part is keeping an open mind and searching for fresh ideas.
小题3:____________
Suppose you had everything you wanted. Would you be happy without anyone to share it with? The personal relationships we develop with friends and family members are the greatest source of happiness in our lives. Don't forget about them. Taking the time to develop and enjoy personal relationships is important to long-term happiness.
小题4:_____________                          
Even if your life isn't perfect, you can always build toward a goal. The best way to do this is working towards a goal. We can’t control everything about our lives, but working towards a goal gives us something positive to focus on and lays the foundation for future success. No matter what your passion is, get out there and start doing something.
小题5:_____________
You only get one body. Once it is ruined, there isn't much you can do about it. Exercise to keep the body working well. Avoid eating too much of damaging substances and unhealthy foods. It may feel terrible at the time but enjoying good health in your later years is worth the sacrifice. 
答案

小题1:A

小题2:C

小题3:E

小题4:D

小题5:F

题目分析:本文主要告诉我们如何让自己的人生幸福,并给出了具体的建议。

小题1:A 根据本段Enjoy life's simple pleasures and save as much as you can. Expensive things don't create lasting happiness. Careful spending will bring you greater enjoyment in the long run.

说明不要追求过于奢侈的生活,要生活的简单一点。那样自己会更快乐,A项内容与本段相符。

小题2:C 根据本段第二句. The best way to grow is life-long education.说明最好的方法就是教育。C项内容与本段相符。

小题3:E 根据本段The personal relationships we develop with friends and family members are the greatest source of happiness in our lives.说明持久的人际关系也是幸福的一个重要的要素。故E项与本段相符。

小题4:D 根据本段第二句The best way to do this is working towards a goal.说明我们要为目标二努力奋斗,故D项与本段相符。

小题5:F 根据本段第一句You only get one body. Once it is ruined, there isn't much you can do about it.说明保持健康的重要性。故F项和本段相符。

点评:从题目设置的角度看,本题侧重对学生把握文章中心段落和各段落的中心句的能力的考查,所以遇到这类题后,要注意把握好文章结构,了解文章中心意思,找到各段落中心句。

单项选择题

抗体与酶都是高分子物质,在进化过程中形成各自不同的使命。它们的结构虽然不同,但却具有两大共性:都是蛋白质,都能高选择性高紧密性地与靶分子结合,抗体特异性地结合抗原且帮助巨噬细胞摄入,并摧毁抗原,酶则高选择性地结合化学反应中特定结构的物质,并催化化学反应,使反应在温和条件下高效率地进行。

但酶的种类与抗体的种类相比简直不可同日而语,已知的酶仅有几千种,而抗体种类千万种之多,从原则上讲,免疫系统能对任何抗原产生抗体,因而抗体的种类是无穷尽的。如果能赋予抗体以酶的催化活性,则无疑可使酶的王国极大地扩展,使温和条件下高选择性高效率的化学反应极大地增加,其前途和效应都是不可估量的。

使抗体兼具有酶的性质,其难度也是可想而知的,它激励着科学家们孜孜以求、不懈努力地去探索。

抗体酶通常采用诱导的方法,即单克隆技术来制备。因为过渡态极不稳定,是一种稍纵即逝的结构,其寿命约为10-13秒,因此不可能用它对动物进行免疫。用1个或几个其它原子或原子团取代过渡态的特定原子或原子团获得在形状、电性、酸碱性等诸方面与过渡态相似的稳定物质,即过渡态相似物,然后用它作为半抗原和载体蛋白一起对动物进行免疫,最后取免疫动物的脾细胞与骨髓肿瘤细胞进行杂交,其杂交细胞就会源源不断地分泌单克隆抗体,经筛选和纯化,可得抗体酶。

抗体酶亦可用拷贝的方法获得。用有已知酶的动物作为抗原动物,抗原通过单克隆技术,制得抗该种酶的抗体。再以此种抗体免疫动物,再次采用单克隆技术,经筛选与纯化,就可获得具有原来酶活性的抗体酶。因为抗原与该抗原产生的抗体具有互补性,经过上述两次拷贝,就把酶的活性部位的信息翻录到抗体酶上,使该抗体酶能高选择性地催化原酶所催化的反应。这种方法虽然不能产生新的催化反应,但对自然界来源稀少的紧缺酶,不失为一种有价值的有潜力的方法。

抗体酶的另一来源为天然抗体酶。近来,已在患全身红斑狼疮病的病人血清中分离出抗体酶,它具有催化水解DNA的活性。这提示人们:在有免疫性缺陷的病人体内存在着抗体酶。

此外,通过基因工程、蛋白质工程和化学修饰等方法亦可制得抗体酶。将编码的人工合成的基因转入细菌或酵母的表达系统,采用突变手段随机产生抗体,经筛选和纯化可得抗体酶;或对抗体进行化学修饰,引入酶的催化基因,把抗体改造为抗体酶。

可以预期,随着科学的不断进步,抗体酶的制备方法将日益先进。多克隆技术、多次免疫和细胞杂交的交替应用、基因工程等将会不断地推陈出新;更方便更快捷更廉价的生产技术将会不断涌现,因此抗体酶的性能也会不断地提高。

抗体与酶的两大共性是()。

A.都是蛋白质,都能高选择性高紧密性地与靶分子结合

B.特异性地结合抗原且帮助巨噬细胞摄人,并摧毁抗原,高选择地结合化学反应中特定结构的特质,并催化化学反应,使反应在温和条件下高效率地进行

C.都能高选择性高紧密性地与靶分子结合,结合抗原且帮助巨噬细胞摄入,并摧毁抗原

D.都是蛋白质,都能高选择性地结合化学反应中特定结构的物质,并催化化学反应,使反应在温和条件下高效率地进行

单项选择题