02-09-07 02-09-12 02-09-16 请教

7. Learning that takes place in infancy provides the____ for the eventual transformation of a child

into an adult. D

A. foundation is necessary

B. necessary foundation is

C. necessary in the foundation

D. foundation necessary

答案D 能理解为什么选这个 但请问C为什么错呢

12. In the metals industry, hydrogen is used to prevent metals from tarnishing while

undergoing_____.

A. treated by heat

B. heat treatments

C. by heat treatments

D. heat-treated

答案B 主要是对while后面整个成分不太理解 是作为从句吗？那主 谓 宾呢

16.   ？Although the term "corrosion" applies mostly to metals and particularly to their

   A                                                               

reaction to oxygen, all material are subject to surface deterioration.

B                    C                      D

C不对是应该前面加the吗？

7、句子还是没理解。原意是“提供了一个必要的基础”（provide sth1 for sth2/sb)necessary形容词作后置定语。

C项，necessary作名词是生活必需品的意思,provides necessary in the foundation ...在地基上提供生活必需品，虽然这句勉强可以过得去，但跟后面意思一点关系也没有了。

12、while(it is)undergoing heat treatments.

13、materials.   前面有限定词all 了，不要再加冠词。但可以出现all of the N.

1.c 错, 是因为the 后面要接名词foundation,而不是形容词necessary;此外, 就算形容词可用,C也该变了原句的逻辑意思.

2.while 从句在主语一致的情况下可省主语和be 动词,意思不变,落实到本句,则是省略了metals are.

3."material" should be "materials", because "are".

12. In the metals industry, hydrogen is used to prevent metals from tarnishing while metals are undergoing heat treatments.

主句的主语hydrogen 从句的主语是metals

两个主语不一样，怎么可以省略metals are呢？