1.Infact,weallneedreturntonature.答案中此处填a,我觉得也可以不填,做情态动词用,但是答案中说不可以,2.CouldithavebeeninthosedifficultsituationsReagandevelopedtheoptimisticspiritthatwouldserve

Question

1.In fact,we all need _____ return to nature.
答案中此处填a,我觉得也可以不填,做情态动词用,但是答案中说不可以,
2.Could it have been in those difficult situations _____ Reagan developed the optimistic spirit that would serve him so well?
A.that B.which为
什么只能填that不能填which?

Answer 1

1.In fact,we all need _____ return to nature.
答案中此处填a,我觉得也可以不填,做情态动词用,但是答案中说不可以,请解释一下
答：你的想法有一定道理.但是：
1.need 作情态动词多用于非肯定句.
2.即使偶尔也可能用于肯定句中,我们看all这个词与情态动词的位置可以看出,这个need更象个实义动词而非情态动词：We can all do sth. We may all do sth. We must all do sth.
加上“正确”答案只有一个,当然不承认你的说法了.
2.Could it have been in those difficult situations _____ Reagan developed the optimistic spirit that would serve him so well?
A.that B.which为
什么只能填that不能填which?
答：因为这是某人造出的所谓的变形的强调句：It is/was +状语+that +句子剩余部分（的一般疑问句） 造句者将这个be动词改成了could have been了.这样的“强调句”其实很少见.
你可能认为这也可以理解为限制性定语从句.这有两种说法是不可能的：
1. 限制性定语从句先行词前不用指示代词而用the,因为指示代词是用手指着说的,所以不需要后置限制性定语.
2. 关系代词which/that在定语从句中作主语或宾语.但Reagon .至句尾不缺乏主语和宾语.
你也许还认为那是一个同位语从句.但同位语从句的陈述句是用that不用which, which引导同位语从句时,其先行词必为question 之类的词.
所以这一空不能填which