这道题主要从句子结构、动词方面来判断就可以了
【下面是mark过来的解析】
A. should it be that结构错误，应为：should test scores show that…；that后面接的从句没有谓语动词。
B. should it be that结构错误；that后面接的从句主语为mastery，因此谓语应为单数has。
C. should位于句首引起虚拟语气下的条件状语从句，要是完整的句子，该句的showing应为show。
D. if条件状语从句没有谓语，showing应改成show。
E.正确。

1、if引导条件状语从句,从句可为真实条件从句,也可为虚拟条件从句。如为真实条件从句,谓语用陈述语气,表示“假使”“如果”,if+一般现在时，sb do/may/can/will do sth，后者的区别在于：do表示确定发生，may表示可能发生，will表示将来。如：If Sophie eats pizza, then she becomes ill. VS If Sophie eats pizza, then she may become ill. VS If Sophie eat pizza tomorrow, then she will become ill.

2、if引导的条件不可能发生的，用虚拟语气，强调过去没有发生用if past perfect(had done), then conditional perfect(would have done)；强调现在不可能发生用if past, then past future(would do)，或 if were to, then past future；强调未来不可能发生用if should do, then past future。

3、助动词were,should,had可以移至主语前倒装,if可省略。
如：If Sophie had eaten pizza, then she would have become ill.=Had Sophie eaten pizza, then she would have become ill
If Sophie were to eat pizza, then she would become ill.=Were Sophie to eaten pizza, then she would have become ill
If it should rain tomorrow, I would stay at home.=Should it rain tomorrow, I would stay at home.

If从句如果有were/had/should可以倒装，并把if省略。 should后面跟动词原形。

show that

这里E是单纯的条件状语从句，满足主将从现的原则，至于为什么前面是would，我认为这里是用了would的情态动词形式，语气偏弱一点

原句句子结构：Several educational research groups are denouncing the mayor's proposal of a system…
原句逻辑语义：一些教育研究团体谴责市长的提议，市长提议的这个系统规定个别教师将获得加薪或奖金，取决于学生在学习掌握阅读技巧九个月之后的考试成绩分数。

A. should it be that结构错误，应为：should test scores show that…；that后面接的从句没有谓语动词。
B. should it be that结构错误；that后面接的从句主语为mastery，因此谓语应为单数has。
C. should位于句首引起虚拟语气下的条件状语从句，要是完整的句子，该句的showing应为show。
D. if条件状语从句没有谓语，showing应改成show。
E.正确。

倒装结构，正常的语序（虽然ron说不要串改题目），Several educational research groups are denouncing the mayor's proposal that if the test scores show that their students mastery of reading skills has improved, indiviual teachers would be given raises or bonuses by a system.
A&B it没有指代，绝对错误
C&D 主句没有谓语动词，绝对错误。

老师，我想问一下，是否虚拟语气里面主句的将来时(will)可以改变时态为过去将来时(would)来表示这件事情尚未发生。也就是说通过故意的错乱时态达到表达意思的目的。我记得你课上说过这个东西——外国人对时态非常敏感，一旦时态不对他们能很快的识别出来这个是一个虚拟语气。

(E)中的has修饰mastery of reading skills？？不看their students'吗？？