難句解析：
①Emerging from the 1980 census is the picture of a nation developing more and more regional competition, as population growth in the Northeast and Midwest reaches a near standstill.
▲這是主從復(fù)合句，逗號(hào)前面是主句，是個(gè)倒裝句，主干句其實(shí)是The picture is emerging from the 1988 census。倒裝的原因是這個(gè)句子的主語the picture后面有一個(gè)of引導(dǎo)的很長(zhǎng)的修飾成分，其中nation后面跟隨的分詞短語表述了nation的某種狀態(tài)；逗號(hào)后面是as引導(dǎo)的從句表示伴隨，基本結(jié)構(gòu)是population growth reaches a standstill。
△認(rèn)識(shí)到第一個(gè)分句的倒裝構(gòu)成，nation后面的分詞結(jié)構(gòu)是對(duì)nation的表述；再者就是要搞清楚兩個(gè)分句之間并列轉(zhuǎn)折的關(guān)系。
②This development — and its strong implication for US politics and economy in years ahead — has enthroned the South as America's most densely populated region for the first time in the history of the nation's head counting.
▲首先不看破折號(hào)之間的內(nèi)容，找出這個(gè)句子的主干：This development has enthroned the South as region。再看各個(gè)部分的修飾成分：主語后面的破折號(hào)之間是對(duì)主語的補(bǔ)充，即this development產(chǎn)生的另一種暗示，注意其中介詞for和in的用法；然后看region后面的狀語for the first time in the history（有史以來第一次）。
△注意破折號(hào)之間的插入部分在意義上是主語的補(bǔ)充部分；enthrone和head counting對(duì)這個(gè)句子的理解很關(guān)鍵。注意head counting是census通俗的說法。
③Nonstop waves of immigrants played a role, too — and so did bigger crops of babies as yesterday's "baby boom" generation reached its child-bearing years.
▲這是由兩個(gè)分句組成的并列句，只不過第二個(gè)分句簡(jiǎn)化了一下。第一個(gè)分句很簡(jiǎn)單，主干是immigrants played a role。主語immigrants前面是其修飾成分。第二個(gè)分句是個(gè)主從復(fù)合句，主句是倒裝形式，還原過來應(yīng)該是Bigger crops of babies also played a role。因?yàn)榍懊嬉呀?jīng)提到了played a role，為了簡(jiǎn)潔，用so前導(dǎo)，后跟助動(dòng)詞did加主語就可以了；as引導(dǎo)了一個(gè)原因狀語從句，指出這種情況發(fā)生的社會(huì)原因。
△關(guān)鍵是要理解破折號(hào)后面倒裝句的構(gòu)成與意義，這樣就會(huì)明白這個(gè)句子要說明的就是影響人口增長(zhǎng)的兩個(gè)原因：immigrants和bigger crops of babies，crop在這里是“大量，大批”的意思。
④Often they choose — and still are choosing — somewhat colder climates such as Oregon, Idaho and Alaska in order to escape smog, crime and other plagues of urbanization in the Golden State.
▲我們先來分析這個(gè)單句的主干結(jié)構(gòu)：They choose and are still choosing colder climates in order to escape...。注意破折號(hào)之間是謂語動(dòng)詞的補(bǔ)充，表示另一種時(shí)間狀態(tài)。在climates后面跟的是such as引導(dǎo)的三個(gè)州名，列舉的是較為寒冷的幾個(gè)州；后面是一個(gè)由in order to引導(dǎo)的表示目的的短語，其中escape的賓語有三個(gè)：smog，crime and other plagues，of短語修飾plagues，說明plagues發(fā)生的原因。
△在時(shí)態(tài)上注意同一個(gè)謂語動(dòng)詞choose的兩種時(shí)態(tài)，表示的兩個(gè)時(shí)間概念；短語the Golden State是美國(guó)加利福尼亞州的別稱。
⑤As a result, California's growth rate dropped during the 1970's, to 18.5 percent — little more than two thirds the 1960's growth figure and considerably below that of other Western states.
▲這個(gè)句子的結(jié)構(gòu)是由數(shù)字的比較構(gòu)成。第一處在于dropped to 18.5％（下降到了18.5％），不要理解成下降了18.5％；再一個(gè)是two thirds the 1960's growth figure，指的是60年代生長(zhǎng)率的三分之二；below后面的that代替的是growth rate，目的是與其它西部各州相比較。
△對(duì)數(shù)字的理解是這個(gè)句子的關(guān)鍵，注意其中比較的是70年代與60年代、加州與西部其它各州的生長(zhǎng)率。
來源:可可英語 http://www.ccdyzl.cn/kaoyan/201406/307275.shtml