【分析】多重复合句。句子主干是constraints explain...。介词短语on improving productivity是constraints的后置定语，why引导的名词性从句作explain的宾语，其中包含than引导的比较状语从句。

　　【译文】相反，生产力的提高受到限制，正是那里的教育发展得不够快的原因。

　　【点拨】1)on the contrary是固定搭配，意思是“正相反”。2)constraint基本含义是“约束，限制”，通常与on搭配使用，另外它还有“拘束，态度不自然”的意思。

　　【临摹】我没有生病，相反，我健康极了。

　　20.To take this approach to the New Englanders normally means to start with the Puritans' theological innovations and their distinctive ideas about the church —important subjects that we may not neglect.

　　【分析】复合句。句中的两个不定式短语To take…和 to start with...分别作主句的主语和宾语；破折号后的内容补充说明 theological innovations and distinctive ideas，其中包含that引导的定语从句，修饰subjects。

　　【译文】以这种方法看待新英格兰人通常意味着从这些清教徒的神学变革和他们关于教堂的与众不同的理念入手——这些是我们不容忽视的重要主题。

　　【点拨】动词短语take a/an…approach to sth.意思是“对…采用...方法/态度”。

　　【临摹】对新思想采取不存先入之见的态度是明智的。

　　临摹答案

　　1.Students differ in how they learn, depending on the background, experience and aptitude.

　　2.Trains are subject to delays after, the heavy snowfalls.

　　3.The badly wounded take priority for medical attention over those only slightly hurt.

　　15.He must be out of his mind to deride such a brilliant person as a fool.

　　17.Despite her professional success, she is always over shadowed by her husband.

　　19.I’m not sick；on the contrary,I’m in the peak of health.

　　20.It is advisable to take an open-mind approach to new ideas.