①植物对周围环境的反应,最奇妙的莫过于它的生长方向,比如从一粒小小的植物种子萌发开始,它就知道根应该往地下生长,而茎干则伸向天空。这是一个极为普通的现象,然而植物为什么会这样呢它是怎样懂得“上”和“下”的概念呢又是什么力量促使它选择根朝下、茎朝上的生长方向呢怎样解释这种生理机制
②不久之前,美国俄亥俄州立大学的植物学家迈克尔·埃文斯以及他的同事,提出了一个崭新的理论。他们认为,无机钙对于植物的生长方向起着举足轻重的作用。因为他们在研究中发现,在植物的弯曲生长过程中,无论是根冠下侧部位还是芽的上侧部位,都存在着高含量的无机钙。那么无机钙又是如何使植物辨别方向的呢埃文斯解释说,因为根冠有着极为丰富的`含淀粉体的细胞,而这种含无机钙的淀粉体细胞会把其内部的钙送到根冠下侧。这时,如果用特殊的实验手段去阻止钙的移动,植物马上就会表现出不按正常的方式去生长。同样,植物的芽虽然没有冠部,但也含有丰富的淀粉体细胞,淀粉体细胞也能将其内部的无机钙送到芽上侧的细胞中,这显然说明,无机钙对植物生长方向有着不可忽视的重要作用。
③那么,既然淀粉体细胞内有许多无机钙,而淀粉体细胞又能使无机钙在植物体内来去自如,除了重力之外,淀粉体细胞又是*哪一种力量使无机钙如此方便地上下移动呢最近,美国德克萨斯州立大学的研究人员斯坦利鲁在研究中发现,这是由于淀粉体细胞的上端和下端之间的电荷不同,两端电荷的不一致引起细胞极化。结果,为数众多被极化的淀粉体细胞排列在一起,总电荷就强得足够吸引任何相反电荷的钙原子,驱使它们在体内移动。于是斯坦利鲁提出,由于细胞的极性带动钙的移动,从而导致植物茎干总是向上生长,而根则朝地下生长。
④由谁控制植物生长方向的研究课题已日趋深入,这种神奇的力量取决于什么?是无机钙?是细胞的极性还是数者兼有之目前依然有待于更进一步的探索。
12、文中最能说明无机钙对植物生长方向有着不可忽视的重要作用的一项是(3分)
A、植物根冠下侧部位和芽的上侧部位,都存在着高含量的无机钙。
B、植物根冠中含无机钙的淀粉体细胞会把其内部的钙送到根冠下侧。
C、植物的芽中含无机钙的淀粉体细胞能将其内部的无机钙送到芽上侧的细胞中。
D、用特殊的实验手段去阻止无机钙的移动,植物马上表现出不能按正常的方式去生长。
13、对文中第③段内容的理解有错误的一项是(3分)
A、淀粉体细胞的上端和下端之间不一致的电荷引起细胞极化。
B、为数众多被极化的淀粉体细胞排列在一起会产生很强的总电荷。
C、电荷相反能引起相吸是导致无机钙原子流动的科学原理。
D、淀粉体细胞的极性带动无机钙的移动解答了植物生长方向之迷。
12、(3分)D
13、(3分)D
Last Sunday, Jim went out to fly a kite. The kite flew highly in the sky. Jim ran with it happily.
Suddenly the line was broken and the kite flew away. Soon it disappeared. Where was it?
Jim had no idea. So he had to run here and there to look for the kite. At last he saw it on the top of the tree. He tried to get it down. But he couldn’t. He felt sad.
1。 叙述的人称
英语的记叙文一般是以第一或第三人称的角度来叙述的。用第一称表示的是由叙述者亲眼所见、亲耳所闻的经历。它的优点在于能把故事的情节通过“我”来传达给读者,使人到真实可信,如身临其境。如:
The other day, I was driving along the street。 Suddenly, a car lost its control and ran directly towards me fast。 I was so frightened that I quickly turned to the left side。 But it was too late。 The car hit my bike and I fell off it。
用第三人称叙述,优点在于叙述者不受“我”活动范围以内的人和事物的限制,而是通过作者与读者之外的第三者,直接把故事中的情节展现在读者面前,文章的客观性很强。如:
Little Tom was going to school with an umbrella, for it was raining hard。 On the way, he saw an old woman walking in the rain with nothing to cover。 Tom went up to the old woman and wanted to share the umbrella with her, but he was too short。 What could he do? Then he had a good idea。
2。 动词的时态
在记叙文中,记和叙都离不开动词。所以动词出现率最高,且富于变化。记叙文中用得最多的是动词的过去的\',这是英语记叙文区别于汉语记叙文的关键之处。英语写作的优美之处就在于这些动词时态的变化,正是这一点才使得所记、所叙有鲜活的动态感、鲜明的层次感和立体感。
3。 叙述的顺序
记叙一件事要有一定的顺序。无论是顺叙、倒叙、插叙还是补叙,都要让读者能弄清事情的来龙去脉。顺叙最容易操作,较容易给读者提供有关事情的空间和时间线索。但这种方法也容易使文章显得平铺直叙,读起来平淡乏味。倒叙、插叙、补叙等叙述方法能有效地提高文章的结构效果,让所叙之事跌宕起伏,使读者在阅读时思维产生较大的跳跃,从而为文章所吸引,深入其中。但这些方法如果使用不当,则容易弄巧成拙,使文章结构散乱,头绪不清,让读者不知所云。
4。 叙述的过渡
过渡在上下文中起着承上启下、融会贯通的作用。过渡往往用在地点转移或时间、事件转换以及由概括说明到具体叙述时。如:
In my summer holidays, I did a lot of things。 Apart form doing my homework, reading an English novel, watching TV and doing some housework, I went on a trip to Qingdao。 It is really a beautiful city。 There are many places of interest to see。 But what impressed me most was the sunrise。
The next morning I got up early。 I was very happy because it was a fine day。 By the time I got to the beach, the clouds on the horizon were turning red。 In a little while, a small part of the sun was gradually appearing。 The sun was very red, not shining。 It rose slowly。 At last it broke through the red clouds and jumped above the sea, just like a deep-red ball。 At the same time the clouds and the sea water became red and bright。
What a moving and unforgettable scene!
5。 叙述与对话
引用故事情节中主要人物的对话是记叙文提高表现力的一种好方法。适当地用直接引语代替间接的主观叙述,可以客观生动地反映人物的性格、品质和心理状态,使记叙生动、有趣,使文章内容更加充实、具体。试比较下面两段的叙述效果:
I was in the kitchen, and I was cooking something。 Suddenly I heard a loud noise from the front。 I thought maybe someone was knocking the door。 I asked who it was but I heard no reply。 After a while I saw my cat running across the parlor。 I realized it was the cat。 I felt released。
这本来应是一段故事性很强的文字,但经作者这么一写,就不那么吸引人了。原因是文中用的都是叙述模式,没有人物语言,把“悬念”给冲淡了。可作如下调整:
I was in the kitchen cooking something。 "Crash!" a loud noise came from the front。 Thinking someone was knocking at the door, I asked, "Who?" No reply。 After a while, I saw my cat running across the parlor。 "It's you。" I said, quite released。
导入:
第1段:提出一种现象或某个决定作为议论的话题
As a student, I am strongly in favour of the decision. (亮明自己的观点是赞成还是反对
The reasons for this may be listed as follows. (过渡句,承上启下
正文:
第2段:First of all... Secondly... Besides...(列出2~3个赞成或反对的`理由
结论:
第3段:In conclusion, I believe that... (照应第1段,构成\"总—分—总\"结构
This is my first week in ** Senior Middle School.Everything here is new for me.Our school is an old school but it`s very beautiful.I have 50 new classmates in my class.They`re all very excellent, I think, and I felt a little sad.Because I`m too common.But come to think of it,it`s a very good thing.I believe I can also be very excellent if I study with such excellent classmates.I didn`t know why Ms *** chose me to be the committee of study.But I know it`s a good chance for me to raise my ability.All I can do is do my best in the future.I am sure that Ms *** and my classmates can help me when I do something wrong. Because they`re all very kind.It`s a pleasure to work and study with them.I`m really very happy.I`m not an outstanding student in this class,but I can do the same thing like others.I believe I won`t make anyone disappointed.
导入:
第1段:Some people hold the opinion that A is superior to B in many ways. Others, however, argue that B is much better. Personally, I would prefer A because I think A has more advantages.
正文:
第2段:There are many reasons why I prefer A. The main reason is that ... Another reason is that...(赞同A的原因
第3段: Of course, B also has advantages to some extent... (列出1~2个B的优势
结论:
第4段: But if all these factors are considered, A is much better than B. From what has been discussed above, we may finally draw the conclusion that ...(得出结论 オ
1。 头绪分明,脉络清楚
写好记叙文,首先要头绪分明,脉络清楚,明确文章要求写什么。要对所写的事件或人物进行分析,弄清事件发生、发展一直到结束的整个过程,然后再收集选取素材。这些素材都应该跟上述五个“ W ”和一个“ H ”有关。尽管不是每篇记叙文里都必须包括这些“ W ”和“ H ”,但动笔之前,围绕五个“ W ”和“ H ”进行构思是必不可少的。
2。 突出中心,详略得当
在文章的框架确定后,对支持故事的素材的选取是很关键的。选材要注意取舍,应该从表现文章主题的需要出发,分清主次,定好详略。要突出重点,详写细述那些能表现文章主题的重要情节,略写粗述那么非关键的次要情节。面面俱到反而使情节罗列化,使人不得要领。这一点是写好记叙文要解决的一个基本问题,也需要一定的技巧。如:
One night a man came to our house and told me, "There is a family with eight children。 They have not eaten for days。" I took some food with me and went。
When I finally came to that family, I saw the faces of those little children disfigured (破坏外貌) by hunger。 There was no sorrow or sadness in their faces, just the deep pain of hunger。
I gave the rice to the mother。 She divided the rice in two, and went out, carrying half the rice。 When she came back, I asked her, "Where did you go?" she gave me this simple answer, "To my neighbors — they are hungry also!"
3。 用活语言,准确生动
记叙文要用具体的事件和生动的语言对人、事、物加以叙述。一篇好的记叙文的语言既要准确、生动,又要表现力强,这样才能把人、事描写得具体生动,其可读性才强。试比较下面一篇例文修改的前后效果。
原文:
One day Xiaoqiang was wandering away。 He was soon lost among people and traffic。 He could not find the way back home and started crying。 Just then, two young students who were passing by found him standing alone in front of a shop and crying。 They went up to Xiaoqiang and asked him what had happened。 Xiaoqiang told them how he got lost and where he lived。 The two students decided to take him home。 Mother was pleased to see Xiaoqiang come back safe and sound。 She invited the two students into the house and gave them some money, but they didn't take it。 She served them with tea but they left。
修改后:
The other day, five-year-old Xiaoqiang left home alone and wandered happily in the street。 After some time, he felt hungry so he wanted to go back home。 But he found he was lost among the crowded people and heavy traffic。 When he could not find the way home, he started and crying。 Just then, two young students who were passing by from school found him sanding crying in front of a shop。 They immediately went up to him。
"Little boy, why are you standing here crying?" they asked。
"I want Mom, I go home。" said the boy, still crying。
"Don't worry, we'll send you home。"
And they spent the next two hours looking for the boy's house。 With the help of a policeman, they finally found it。
When the worried mother saw her son come back safe and sound, she was so thankful and she invited the students into her house。 Gratefully, she offered them some money, saying it was a way to express her thanks, but the young students firmly refused it and left without even a cup of tea。
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