The following questions present a sentence, part of which or all of which is underlined. Beneath the sentence, you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise choose one of the others.
These questions test correctness and effectiveness of expression. In choosing your answer, follow the requirements of standard written English; that is, pay attention to grammar, choice of words, and sentence construction. Choose the answer that produces the most effective sentence; this answer should be clear and exact, without awkwardness, ambiguity, redundancy, or grammatical error.
In his study on the failures of the American educational system, Professor Harris states that over two million high school seniors in this country are functionally illiterate, and at least as much as four million others cannot read at an eighth-grade level.（）
A. at least as much as four million others cannot
B. at least as many as four million and more cannot
C. more than four million of other students are unable to
D. there was at least four million other students unable to
E. more than four million others cannot
缺失，可摘局部义齿修复，基牙
Ⅰ度松动，这种情况下，