考研英語：歷年真題閱讀要點(diǎn)之1991-Text 3

　　C. R. Barnes has suggested that it is as proper to term the plant a water structure as to call a house composed mainly of brick a brick building.

　　suggest可以表示“認(rèn)為”;it充當(dāng)形式主語，真正的主語是to term the plant a water structure，也就是說，其實(shí)這個句子就是to term the plant a water structure is as proper as to call a house composed mainly of brick a brick building“稱植物為水建筑和稱主要由磚砌成的房子為磚建筑一樣合適”;as...as...為比較結(jié)構(gòu);term“把...叫做”;be composed of“由...組成”。

　　Certain it is that all essential processes of plant growth and development occur in water.

　　正常語序it is certain that...其中，it充當(dāng)形式主語，真正的主語是that引導(dǎo)的主語從句;certain提前，起到強(qiáng)調(diào)作用;essential“基本的，必要的”，常見搭配be essential to“對...必不可少”，比如Environmental protection is essential to social development.

　　The processes of photosynthesis, by which carbon dioxide and water are combined -- in the presence of chlorophyll and with energy derived from light -- to form sugars, require that carbon dioxide from the air enter the plant.

　　by which carbon dioxide and water are combined to form sugars為非限定性定語從句，充當(dāng)插入語，起到補(bǔ)充說明的作用，可以略過，題干涉及另當(dāng)別論;in the presence of chlorophyll and with energy derived from light為兩個破折號之間的內(nèi)容，同樣充當(dāng)插入語;也就是說，這個句子應(yīng)該重點(diǎn)關(guān)注的內(nèi)容是The processes of photosynthesis require that carbon dioxide from the air enter the plant.

　　42. The essential function of photosynthesis in terms of plant needs is ________.

　　[A] to form sugars

　　[B] to derive energy from light

　　[C] to preserve water(A)

　　[D] to combine carbon dioxide with water

　　題干涉及“就植物的需求而言，光合作用的基本功能。”也就是說，解題的時候，我們要返回原文，關(guān)注一下by which carbon dioxide and water are combined to form sugars這個插入語，“光合作用合成糖分”。結(jié)合上文The carbon dioxide (CO2) from the air may enter the leaf as a gas but is dissolved in water in the leaf before it is combined with a part of the water to form simple sugars -- the base material from which the plant body is mainly built.可知，本題選A。另外，各位同學(xué)精讀的時候，不用關(guān)注文中出現(xiàn)的生僻詞匯和專業(yè)術(shù)語，考查的可能性很小。