帮忙做道英语题~~~~~~~~

Question

These problems,( )will seriously affect the growth of teenagers and even the nation's futre.
A.not if solved properly
B.if solved properly
C.if not properly solved
D.if solved not properly

Answer 1

c

Answer 2

答案选C。
1. 状语从句的省略：if not properly solved=if these problems are not properly solved 如果这些问题没有得到适当解决的话
2. 该语法简介如下：
状语从句的省略条件:
1). 从句主语与主句主语相同，或者从句主语是it。
2). 从句主语的谓语动词以be动词开始。
如果以上两个条件同时符合,就可以把从句的主语和be动词同时省略.
此种现象常用于时间/条件/让步状语从句,连词一般有when/while/once/if/unless/though/although等.
3. 再回到该题，该条件状语从句if these problems are not properly solved中的主语与主句主语these problems一样，谓语动词以are开头，所以可以把从句的these problems are一起省略。

Answer 3

C