你能说出苏姗与她妹妹的共同之处吗？ 2．differ vi. 相异；有区别；不同于 主要用法：
①different adj. 不同的，有区别的；有差异的 difference n. 差别；差异；不同之处 ②A differ from B. A不同于B 相当于： A be different from B. A and B differ from each other.
例 如：French differs from English in this aspect.
在这方面法语和英语不同。
也可说：French and English differ ( from each other) in this aspect. French is different from English in this aspect.
③differ with sb. about /on /over sth. 与某人意见不同，持不同看法；不同意 相当于：disagree with sb. 例 如：
I have to differ with you on that.
在这一点上我不同意你的看法。
Medical opinion differs about /on how to treat the disease.
关于如何治疗这种疾病医学上有不同的看法。拓展：
④tell the difference between A and B 说出A和B的不同之处
I can never tell the difference between the twins. 我从来都分不清这对双胞胎。
⑤make a /no /some, etc. difference (to /in /sb. /sth.).
对某人/某物有（或没有，有些等）作用，关系，影响 例 如：
The rain didn’t make much difference to the game.
这场雨对比赛没多大影响。
Your age shouldn’t make any difference to whether you get the job or not.
你能不能得到这工作与你的年龄无关。
Changing jobs made a big difference to my life. 转学对我的一生有重大影响。 3．round up 主要用法：
①将……聚拢起来；使聚集 （to find and gather together people, animals or things）
结构：round up sb. /sth.或round sb. /sth. up.
例如：
I round up a few friends for a party.
我找了几个朋友聚了聚。
The cattle are rounded up in the evenings. 到了晚上牛都要圈起来。
②围捕 （to find and arrest /capture sb.） The suspect was rounded up and questioned.
嫌疑犯被捕并受到审问。
4．strengthen vt. &vi. 加强；增强；巩固（to become stronger; to make sb. /sth. stronger） 例如：
Her position in the party has strengthened in recent weeks.
最近几个星期以来她在党内的地位有所加强。（vi.）
The wind had strengthened overnight. 夜里，风更大了。（vi.）
Repairs are necessary to strengthen the bridge. 这座桥需要加固。（vt.）
We should strengthen our national defence. 我们应该巩固我们的国防建设。（vt.） 拓展：
strength n. 体力；力气；力量 with strength 用力气
strong adj. 强壮的；强健的 主要强调人体的力量
He is strong. =He is a person of great strength. He pushed against the rock with all his strength. 他用全力推那块石头。
5．diverse adj. 不同的；相异的；多种多样的；形形色色的
主要用法：
①diverse adj. 相当于 various ②diversity n. 相当于 variety ③a diversify of 相当于 a variety of
④diversify v. （使多样化，变化；不同）相当于 vary v. 例如：
Guests are absent for diverse reasons.
客人们由于各种不同的原因缺席。（various） 相当于：Guests are absent for a diversity of reasons.（a variety of）
The reasons for guests’absence diversify. (vary)
6．break out 突然发生（多指火灾；战争；疾病等）begin suddenly 主要用法：
①没有被动语态，例如：
The Second World War broke out in 1939. 第二次世界大战爆发于1939年。 A fire broke out in a factory yesterday. 昨天一家工厂发生了火灾。
②联想“发生”的相关词组及单词（它们都没有被动语态）
happen, occur, take place, come about ③拓展：break up /break down /break in break up：
①使碎开；打碎
The stricken tanker began to break up on the rocks.
被击中的油船触礁后开始断裂了。
②把……分成几部分
I want to plant more bushes to break up the garden a bit.
我想多种些矮树丛把花园稍微分隔成几部分。③使停止，制止
Three policemen were needed to break up the fights.
需要三名警察制止这场斗争。
④破裂，瓦解
If a parent dies, the family may break up.
如果父母中有一人去世，这个家可能就散了。break down
①（机器等）停止运转；出故障
The elevators in the building are always breaking down. 这幢楼里的电梯总出故障。
②失败（讨论，谈判等）
Peace talks have broken down over the question of reparations.
和谈因战后赔款问题而中止。
③弄坏，打破
Tom broke down the door of our classroom last week.
汤姆上周把我们教室的门弄坏了。
④改变固有想法
It’ll be difficult to break down their prejudices about lesbians.
很难改变他们对女同性恋者的固有偏见。
⑤化学变化
Bacteria break down the animal waste to form methane gas.
细菌使动物粪便分解成沼气。
⑥精神崩溃，身体垮掉
If Tim carries on working like this, he’ll break down sooner or later. 如果蒂姆继续这样工作，身体迟早会垮掉。
break in
①闯入（行窃）
Someone broke in and took several computers.
有人闯入屋内，偷走了几台电脑。
②打断，插嘴
Dad would occasionally break in with a suggestion.
爸爸偶尔会插话，提出建议。
二、本单元重、难点句子
1．These peoples came to the continent at least fifty thousand years ago and created complex societies.
这些人至少在五万年以前就来到这块大陆，而且创建了复杂的社会群体。
people在这里是“民族，种族”（race, nation）.又如：
The Chinese are a hard working people. 中华民族是一个勤劳的民族。
the peoples of Africa 非洲各民族
people还可表示“人们”，“人民”是集合名词。当作“人们，一般人”讲时，前面通常不加定冠词；当作“人民”讲时，前面需加定冠词the.如： People from all over the world will gather in Beijing to celebrate the 2008 Olympic Games in Beijing.
来自世界各地的人将会在2008年聚集在北京，庆祝2008年的奥运会。 He is a good son of the people. 他是人民的好儿子。
2．In area it is approximately the same size as the USA (without Alaska)which, however, has more than fourteen times as many people.
澳大利亚的面积约有相当于美国（不包括阿拉斯加），而美国的人口确是澳大利亚的14倍多。 （1）本句省略了…more than fourteen times as many people as (Australia)中的as Australia. （2）which在句中引导一个非限制性定语从句，修饰先行词the USA.
（3）approximately (adv.)：nearly; about大约地；大概地
（4）英语中倍数的表达法： ①倍数＋as＋adj.（原级）＋as
例如：Their classroom is twice as big as ours.
他们教室是我们教室的二倍大。
（注意：二倍最好用twice，三倍及三倍以上都可用数词＋times.）
②倍数＋adj.（比较级）＋than
例如：Their classroom is twice larger than mine.
他们的教室比我们的教室大两倍。
③倍数＋n.（比较的尺寸、大小等名词）＋of
例如：Their classroom is twice the size of ours. 他们的教室比我们的大两倍。 ④倍数＋that /those of
例如：Our classroom is twice that of theirs. 我们的教室是他们的两倍。
3．The climate is different depending on the area. 气候情况因地区不同而各异。
①depending on the area在句中作伴随状语，其逻辑主语是句子的主语the climate。此句也可写为：Depending on the area, the climate is different. 拓展：
②It (all) depends 那得看情况，为固定用法，也可写为：That depends. －It he coming? 他来吗？
－That depends. He may not have the time. 那要看情况。他不一定有时间。
③depend upon it 毫无疑问；没错（固定短语），相当于 I'm sure that …
Our work will be finished this week, depend upon it.
我们的工作这暑期可以完成。
Unit 4 Green world
一、本单元重、难点单词及词组 1．promote vt.
（1）促进，鼓励；推动（help sth. to develop and be successful）
The organization works to promote friendship between nations.
该组织旨在促进各国之间的友谊。 Fertilizer promotes leaf growth. 肥料促进叶子的生长。
（2）促销；推销（make people know some product /firm by advertising or offering a reduced price） Many companies make use of ads to promote their products.
很多公司利用广告来推销他们的产品。 （3）倡议；提倡（try to persuade people to believe /support）
This passionate speech promoted equality.
这个充满激情的演讲宣扬平等。
（4）提升；晋升（give sb. a better job /position）
Helen was promoted to senior manager. 海伦被提升为高级经理。
The football team was promoted to the first division.
该足球队已经晋升为甲级队。（promote sb. to＋职位） 2．appetite n.
（1）欲望；食欲；胃口（a desire for food ） She has completely lost her appetite since the operation.
自手术以后，她完全没有食欲。
All that walking has given me a big appetite. 走了那么多路，我胃口好极了。 （give sb. an appetite=make sb. want to eat） 相关搭配：have a huge /big /voracious appetite 食欲好；胃口好
spoil /ruin one’s appetite 影响食欲；倒胃口
（2）欲望；喜爱（a desire or liking for a particular activity）
Pall has no appetite for hard work. 保罗不喜欢卖力气。 3．appoint v. （1）任命
They have appointed a new manager.
他们已经用了一位新经理。（appoint sb.）
Who shall we appoint (as) chairperson?
我们选派谁担任主席呢？（appoint sb. as sth.）
He was appointed to the vacant post. 他被委派填补那个空缺。（appoint sb. to＋place）