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“认为”；it充当形式主语，真正的主语是to term the plant a water structure，也就是说，其实这个句子就是to term the plant a water structure is as proper as to call a house composed mainly of brick a brick building“称植物为水建筑和称主要由砖砌成的房子为砖建筑一样合适”；as...as...为比较结构；term“把...叫做”；be composed of“由...组成”。
Certain it is that all essential processes of plant growth and development occur in water.
正常语序it is certain that...其中，it充当形式主语，真正的主语是that引导的主语从句；certain提前，起到强调作用；essential“基本的，必要的”，常见搭配be essential to“对...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为非限定性定语从句，充当插入语，起到补充说明的作用，可以略过，题干涉及另当别论；in the presence of chlorophyll and with energy derived from light为两个破折号之间的内容，同样充当插入语；也就是说，这个句子应该重点关注的内容是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
题干涉及“就植物的需求而言，光合作用的基本功能。”也就是说，解题的时候，我们要返回原文，关注一下by which carbon dioxide and water are combined to form sugars这个插入语，“光合作用合成糖分”。结合上文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，本题选A。另外，各位同学精读的时候，不用关注文中出现的生僻词汇和专业术语，考查的可能性很小。
发表于 2017-5-16 17:28:32