Many scholars [U]regard the pre-Hispanic civilizations of Peru as[/U] the most impressive in South America.
A.
B. regard the pre-Hispanic civilizations of Peru to be
C. regard the pre-Hispanic civilizations of Peru to have been
D. consider that the pre-Hispanic civilizations of Peru are
E. consider the pre-Hispanic civilizations of Peru as
这道题的答案为（A），但我觉得A和E没有任何区别。据我自己以前的理解：consider(regard)... to be + adj. 而consider(regard)...as + n. 所以这道题的答案应该选（B）。
In gmat, the idiomatical expressions go like these: regard sth as sth, consider sth to be sth or consider sth sth. Consider sth as sth is strictly porhibited here.
