请教大全534。537。549

(A) No less an authority than

(B) Nonetheless an authority

(C) Nevertheless authoritarian

(D) Not less an authority than

(E) An authority not less than

    答案是A，             但我不太明白这句话到底是什么意思，主语是那个，另外NO LESS THAN 放在句首应该怎么用。

1.                             Not all employment selection mechanisms that have a “disparate effect,” that is, that screens out a percentage of minorities or women disproportionate to their presence in the relevant labor market, are unlawful.

(A) that is, that screens out a percentage of minorities or women disproportionate to

(B) which means, that screens out a percentage of minorities or women disproportionate with

(C) which means, that screen out a percentage of minorities or women disproportionate with

(D) that is, that screen out a percentage of minorities or women disproportionate to

(E) that is, that screens out a percentage of minorities or women disproportionate with

    答案是D，             请详细解释一下句意和结构，几个THAT 把我都搞混了

1.                             Once an apolitical confrontation of the world’s best athletes, the Summer Olympics have been increasingly politicized in recent years as the superpowers have denied many of the best athletes’ access to competition.

(A) been increasingly politicized

(B) been increasing politicization

(C) been of increasing politicization

(D) politicized, increasingly,

(E) increased politicization

答案是A，整句话的意思？另外.                             Once an apolitical confrontation of the world’s best athletes, 如果是指the Summer Olympics 的话，为什么前后单复不一致呢？