OG11-28请牛牛指点

28. The
rise in the Commerce Department's index of leading economic indicators suggest
that the economy should continue its expansion into the coming months, but that
the mixed performance of the index's indi­vidual components indicates that
economic growth will proceed at a more moderate pace than in the first quarter
of this year.

(A) 
suggest that the economy should continue its expansion into
the coming months, but that

(B) 
suggest that the economy is to continue expansion in the
coming months, but

(C) 
suggests that the economy will continue its expanding in
the coming months, but that

(D)  suggests that the
economy is continuing to expand
            into the coming months, but that

(E) 
suggests that the economy will continue to expand
            in the coming
months, but

 A  Suggest does not agree with the rise；that should be omitted to create a main clause；the verb should be future
tense will continue

请问牛牛，that should be omitted to create a main clause这句解释应该怎么理解呢？

还有这个问题的结构，but前后是两个并列主句还是一个主句一个从句呢？恳请帮忙分析一下句子结构。多谢：）