while at the same time 平行并列的疑问

Jerrylai84

45. (26816-!-item-!-188;#058&003335)

A recent poll indicates that many peoplein the United States hold a combination of conservative

and liberal political views; i.e., theydenounce big government, saying government is doing too

much and has become too powerful, whileat the same time supporting many specific government

programs for health care, education, andthe environment.

(A) they denounce big government, sayinggovernment is doing too much and has become too

powerful, while at the same timesupporting

(B) they denounce big government--theysay that government is doing too much and has become

too powerful--but supporting at the sametime

(C) they denounce big government, theysay that government is doing too much and it has become

too powerful, while they support at thesame time

(D) while they denounce big government,saying that government is doing too much and has

become too powerful, at the same timesupporting

(E) while they are denouncing biggovernment--they say that government is doing too much and it

has become too powerful-- supporting atthe same time

句子结构：A recent pollindicates that …, they denounce…, saying…, while supporting…

i.e.  插入语现在分词结构saying…作denounce的伴随状语，while +      现在分词结构表示“与…同时”的

含义（与they denounce并列）。

考点：句子结构

1)  句子结构

2) while+doing现在分词表达时间状语的方式；

3)  如果动词在不同选项之间分别是从句与主句的谓语，要注意句子结构是否完整，选项是否有主句。

(A) 正确，while doing的特殊用法（详见P1-131补充说明），此处宾语从句的引导词that省略了。

(B) but连接对象不平行，they denounce but supporting。

(C) they denounce…,  与they say that…在逻辑上不平行；it多余。

(D) while引导从句，没有主句；supporting…修饰对象不清楚，有与saying…并列的歧义。

(E)  没有主句；it多余。

请教各位牛人，答案A的解释我没看懂。
While at the same time + 现在分词 构成时间状语，怎么可以跟They denounce 并列呢？ 我理想的并列应该是， They denounce ...saying...while at the same time they support...
望指教.所谓while doing 的用法。
万分感谢