简绍自己的家庭的作文【英语】~

波特兰（英语：Portland）,又译作砵仑,是美国俄勒冈州最大的城市同时也是姆尔特诺默县的县治,位于威拉米特河汇入哥伦比亚河的入河口以南不远的地方.它是美国西北部太平洋地区仅次于西雅图的第二大城市.
波特兰市早在1999年就成为北美第一个拥有现代有轨电车系统的城市.至今该市已拥有300英里长的自行车专用道,未来数年还计划新增数百条.波特兰市居民驾驶的混合动力汽车的数量在北美城市中高居榜首,全市共安装了2000个电动汽车充电站.
①在美国俄勒冈州西北部,为该州最大城市.位于哥伦比亚河支流威拉米特河畔,近两河汇合点,距哥伦比亚河入海口约115公里.人口36.6万（1984）.水、陆、空交通要地,海轮可直达市区.木材、羊毛和农产品的集散地.有木材加工、造纸、金属加工、罐头食品、运输机械、电气设备等工业.有波特兰州立大学等多所大学,是该州文化、教育中心.市内多公园,有著名的国际玫瑰花实验公园,每年6月举行玫瑰节.太平洋国际禽畜展览会每年秋季在这里举行.
②美国缅因州西南部港口城市.临卡斯科湾.人口6.2万（1980）.缅因州及新英格兰北部的经济中心.港口的货运量达2,600万吨（1970）,主要输入石油.有造船、石油加工、木材加工、制鞋、食品加工等工业.渔业很盛.著名诗人朗费罗（1807-1882）诞生地.
2005年7月1日波特兰的人口估计为556,370人*,整个波特兰都市地区的人口估计为两百万人.
波特兰的别称是“玫瑰之城”（这个名字最早出自1905年的刘易斯和克拉克远征百年纪念博览会）,这是因为波特兰的气候特别适宜于种植玫瑰,市内有许多玫瑰园,比如波特兰华盛顿公园里的国际玫瑰试验园.波特兰还有许多其它昵称,比如由于当年城市建设速度较快,砍伐树木剩下的树桩来不及被清理,城市周边布满树桩而被称为“树桩城”；由于河流和桥梁较多而被称为“桥城”、“河城”等等.

要先在http://www.ncbi.nlm.nih.gov/pubmed 网址查询有关序列,再在Primer Premier 5软件中进行引物设计,主要要注意以下几个方面：
① 引物长度
一般引物长度为18~30碱基.总的说来,决定引物退火温度（Tm值）最重要的因素就是引物的长度.有以下公式可以用于粗略计算引物的退火温度.
在引物长度小于20bp时：[4(G+C)+2(A+T)]-5℃
在引物长度大于20bp时：62.3℃+0.41℃(%G-C)-500/length-5℃
另外有许多软件也可以对退火温度进行计算,其计算原理会各有不同,因此有时计算出的数值可能会有少量差距.为了优化PCR反应,使用确保退火温度不低于54℃的最短的引物可获得最好的效率和特异性.
② GC含量
一般引物序列中G+C含量一般为40%~60%,一对引物的GC含量和Tm值应该协调.若是引物存在严重的GC倾向或AT倾向则可以在引物5’端加适量的A、T或G、C尾巴.
③ 退火温度
退火温度需要比解链温度低5℃,如果引物碱基数较少,可以适当提高退火温度,这样可以使PCR的特异性增加；如果碱基数较多,那么可以适当减低退火温度,是DNA双链结合.一对引物的退火温度相差4℃～6℃不会影响PCR的产率,但是理想情况下一对引物的退火温度是一样的,可以在55℃～75℃间变化.
④ 避免扩增模板的二级结构区域及错配
像二级结构、错配等在Primer Premier 5均有判断,最后再加一步同源性分析,避免引物的非特异性扩增.

巴黎圣母院、红与黑、傲慢与偏见、高老头、呼啸山庄、简爱、等,喜欢红与黑、很特别也感人!强烈推荐你”

Kate is one of my best friends.She is slim and pretty with two big eyes and shoulder-length hair.She is friendly and generous so she can always get on well with others.When we have difficulties,she alwasy give us a hand.She is energetic.She likes all kinds of sports,especially table tennis.She is one of the members of our school table tennis team.So she often play tennis for about an hour after school.Her favorite star is Zhan Yining.She wants to be a famous table tennis player when she grows up.
凯特是我最好的朋友之一.她是苗条和漂亮的两只大眼睛和一头及肩直发.她是友好和慷慨的,所以她总是可以得到与他人.当我们有困难,她总是给予我们的手.她精力充沛.她喜欢各种运动的种类,特别是乒乓球.她是我们学校的乒乓球队的成员之一.于是,她经常玩大约一个小时放学后的网球.她最喜欢的球星是詹伊宁.她希望成为一个著名的乒乓球运动员,当她长大.

My friend Kate always has a happy weekend.She usually does her homework and helps her parents with the housework on Saturday morning.In the afternoon,she always goes to the library to read books.In the evening,she surfs the internet and listens to music.On Sunday morning,she always visits her friends and plays table tennis with them.In the afternoon,she revies the lessons with me.In the evening,she prepares for the new lessons and read English.She really has a meaningful weekend.

你看他趴在地上,腿脚都磨破了,
刚才我就喊他不要在台子上跳下来,他不听,
其实我早就远远看见他了.

首先说自己有一个幸福的家庭,接着写自己家有几个人,然后写家庭气氛怎样.下面几段就写发生在你家里的有趣的事或者写发生在你家里的谁的有趣的事或者写一家人和和睦睦的场景.结尾感叹我有一个什么样的家,我爱我家.

My friends
I have two good friends in my class. They're twins.Zhang Jia,Zhang Jie.They look alike.They dress alike and talk alike.In fack,you can hardly tell them apart.But their characters are quite different. Zhang Jia is like her mother. She's quieter than Zhang Jie, and not as active. She likes reading and music. In many ways Zhang Jie is similar to her father.She is more active,and likes outdoor activities best.
Although they're quite different, we are friends.
My classmates
I have many friends in my class. They're lovely and interesting. I would like to introduce some of them. Alice is very cute. She's also kind to everyone and she's very enthusiastic. She's always ready to help everyone, but she is forgetful. She always forgets to bring her textbooks, but our teachers always forgive her. Ben is the most talkative boy in our class. His nickname is “chatterbox.” He has a great sense of humor and he always makes me laugh Linda is a quiet student. She is good at every subject but she never shows off. Allen is a very tall boy. He plays basketball very well and he is on our school team. He often says, “playing basketball is good for your health. How about your classmates? Do you like them? Try to admire your classmates. You will be happier
I have a new deskmate this new term. His name is Zhang Gao, male.He is 1.8 metres in height. He looks like a sportsman for sun-tanned skin.Strongly-buih body and well-developed figure make him quite healthy.There is a pair of big eyes below his thick eyebrows. He speaks very fast and fluently, but what he says is very clear. When he speaks, he is always making some gestures. He dreams of being an actor and I have no doubt that his dream will come true. Whenever he sees you,he always gives you a friendly smile which makes you comfortable. He is a good student. I hope he will have a wonderful future. I like my new deskmate.
How do you get on with your classmates? I think it's easy to answer that question.
If you meet up with your friends, you can say, "Hello!" Your friends must be happy, they will think that you are a polite girl or a boy!
If your friends have some questions, you should help them. They'll thank you for your help.
My classmates are very helpful and polite. If one of my classmates has some problems, my classmates will help them solve it. So they are excited.
We help each other and take care of each other.
I hope you can be a polite and helpful child, and I hope you can get on well with all of your classmates.