45. However, it has been found that even peopleinsensitive to a certain smell at first can suddenlybecome sensitive to it when exposed to it oftenenough.
46. The explanation for insensitivity to smell seems to be that the brain finds it inefficient tokeep all smell receptors working all the time but can create new receptors if necessary.
47. The brain finds it best to keep smell receptorsavailable for unfamiliar and emergency signals suchas the smell of smoke, which might indicate thedanger of fire.
48. Many theories concerning the causes of juvenile delinquency (crimes commited young people)focus either on the individual or on society as the major contributing influence.
考研英語長難句解析:
第45題:
【分析】多重復合句。句子主干為 it has been foundthat...,it 作形式主語,真正的主語為 that 引導的主語從句。該從句的主干為 people...can suddenly become sensitive...。其中 insensitive to a certainsmell at first 是 people 的后置定語, when 引導的條件狀語從句省略了主語和系動詞。
【譯文】然而我們卻發現,即使某些人開始時對某種氣味不敏感,如果經常接觸這種氣味,也會對它敏感起來。
【點撥】1) be insensitive to sth."對...不敏感的"。2) be exposed to sth."暴露于;接觸"。
第46題:
【分析】多重復合句。句子主干為 The explanation...seems to be that...。 that 引導表語從句,該從句中由 but 連接的兩個并列句組成;第一個分句中 it 作形式賓語,其后的不定式結構 to keep...作真正的賓語;第二個分句中 if necessary 為條件狀語從句的省略結構, but 前省略相同的主語 the brain。
【分析】復合句。句子主干為 The brain finds it best tokeep smell receptors available。其中 it 為形式賓語,不定式結構 to keep smell receptors available 才是真正的賓語,best 為賓語補足語;such as... 用于舉例,補充說明unfamiliar and emergency signals;which 引導的定語從句修飾 the smell of smoke。
【譯文】大腦發現最好讓氣味感受器隨時用于接收陌生的和危急的信號,比如可能暗示火災危險的煙味。
第48題:
【分析】簡單句。句子主干為 Many theories...focus either on the individual or onsociety。concerning the causes of juvenile delinquency 是分詞短語作后置定語,修飾 theories;括號內的成分是 juvenile delinquency 的同位語,對其進行解釋; as the major contributing influence為賓語補足語。