您正在看的高中二年级是:Saving the earth。 　　▲ one quarter意为“四分之一”，作主语，分数作主语时，其单复数问题主要看该分数所代表的是不是复数名词，如是复数名词，则谓语动词用复数形式，反之用单数形式。

　　Two thirds of the water is polluted.三分之二的水被污染了。

　　Three fourths of the students are League members.四分之三的学生是共青团员。

　　Two thirds of the surface of the earth is covered by water.地球表面三分之二的面积被水覆盖。

　　▲ present是形容词，与be动词连用，表示“有。。。存在”，“出席”。

　　Oxygen is present in the air.空气中有氧气。

　　Lead is present in some gasoline.有些汽油中含有铅。

　　How many people were present at the meeting?有多少人出席了会议?

　　He was the only Englishman present.他是在场的唯一的一位英国人。

　　Carbon is present in many minerals.很多矿物质里含有碳。

　　17.Lakes also have the same problems. Lake Baikal in Asia was once the cleanest in the world, with over 700 different kinds of plants and animals lives.湖泊也存在同样的问题。亚洲的贝加尔湖曾经是世界上最清洁的湖，湖里有700多种植物和动物。

　　▲ 此处介词with表示“有”，“具有”。

　　Who is that girl with yellow hair and dark eyes?那个黄头发黑眼睛的女孩是谁?

　　He was a little gentleman, with glasses.他是一个小个子的先生，戴着眼镜。

　　He was fat with a little black moustache.他是个留着一小撮黑胡须的胖子。

　　I painted a girl with a pigtail.我画了个梳辫子的姑娘

　　18.Now,however,the waters of this great lake,which is also the world’s deepest (over 1740 meters) have been dirtied by waste from a chemical factory.而如今这个大湖，也是世界上最深的湖(1740多米深)，湖水已被一家化工厂的废物污染了。

　　▲water作“水”解释时是不可数名词，不用复数形式;但当其表示“大量的水”，如海水，湖水或河水时，可用复数形式，类似的还有一些不可数名词，词尾加上s后，其词意生了变化，但与原来的不可数名词又有联系。

　　Paper纸 papers报纸

　　green 绿色 greens绿色蔬菜

　　ash灰 ashes废墟

　　glass 玻璃 glasses眼镜

　　sand 沙 sands沙滩

　　cloth 布 clothes衣服

　　iron 铁 irons镣铐

　　snow 雪 snows积雪

　　▲ dirty在本句中作动词用，意为“弄脏”，在英语中，词类是可以转换的。形容词可转换成动词，名词也可转换成动词。

　　Mr Smith pencilled a note and left it on the table.史密斯先生用铅笔写了张条子留在桌子。

　　I slowed down the car as the traffic light became red.红灯亮了，我减慢车速。

　　When the film began to be shown the hall quieted down.电影开始放映时，大厅里安静下来。

　　It was very cold this morning,but it seems to be warming up.今天早晨很冷，但现在好像暖和起来了。

　　Please warm up the cold meat.请把冷肉热一下。

　　19.In 1989 an oil tanker hit a rock off the northwest coast of Alaska,35,000 tons of oil poured into the sea.1989年，一艘油轮在阿拉斯加西北海岸的海面上触礁，36，000吨油倾入大海。

　　▲pour意为“倾注”，“倾没”，“不断流出”，后面常接into,off,down,out等。

　　The rain came pouring down.大雨倾盆而下。

　　The crowd were pouring out of the football ground.人群从足球场蜂拥而出。

　　Fresh fruit came pouring in from these areas.从这些地区运来大批新鲜水果。

　　He was so worried that sweat began to pour down his face.他是那样着急，汗开始沿着她的面颊流淌下来。

　　▲ pour可作及物动词用，意为“倾，倒”。

　　Let me pour you another cup of coffee.我再给你倒杯茶吧。

　　Then you pour some water over it.然后你就在上面浇些花。

　　▲ Pour可引申为“倾吐”，“讲述”等。

　　She poured out her troubles.她倾诉了心头的烦恼。

　　Then she poured out her tale of misfortune..然后他讲述了自己不幸遭遇。

　　20.The accident was one of the worst in history.More than 34,000 birds and 10,000 animals were killed,4800 square kilometers of ocean were polluted.这是历史上最严重的事故之一，34，000多只鸟和10，000多头动物死亡，4，800平方公里的海洋受到污染。

　　▲one of 后面通常接复数名词，意为“。。。之一”，本句中的the worst 后面省去了accidents以避免重复。

　　Lesson 35

　　1. Three billion years after life began,the earth is now the home to many different kinds living---perhaps five to ten million kinds.生命开始30亿年以后，现在的地球是许多种不同生物的生息之地—也许有500万到1000万种。

　　▲after是连词，在这里引导一个时间状语从句，其前面的three billion years是一个名词性的短语作状语，修饰began。

　　Two days after he returned home,he went out again.他回家两天以后，又出去了。

　　It was three weeks after she left that I found the money she had left to me.在她离开三周以后，我才发现她留给我的钱。

　　【注】由after引导的时间状语从句，在更多情况下是被副词所修饰，我们常见的结构有 soon after,shortly after,long after

　　Shortly after I came home,I got a telephone call saying the manager of our company had an accident.我到家不久就接到了一个电话说我们公司的经理出了车祸。

　　Soon after I left school, heavy rain came pouring down.我离开学校不久，大雨就倾盆而下。

　　▲ home在本句中的意思“动植物的生息之地”。

　　The home of the panda is China. 熊猫的产地是中国。

　　Australia is the home of kangaroos.澳大利亚是袋鼠的产地。

　　2. However, many of these are dying out.It is thought that between the years1550 and 1950 an average of one kind of living thing died out each year.然而其中许多正在走向灭绝，据认为在1550年到1950年之间平均每年就有一种生物灭绝。

　　▲ die out意为“绝种”，“灭绝”，“不复存在”。

　　Many old customs are gradually dying out.有许多旧的风俗习惯正在逐渐消亡。

　　These animals have already d