Question

【题目】As we all know, about 75 percent of the earth_______covered by water.

A. is B. are C. am D. were

Answer 1

【答案】A

【解析】句意：我们都知道，地球的75%被水覆盖。基数词+percent of表示……的百分之几十，由分数修饰的主语后面谓语动词的数，和被修饰主语的单复数保持一致。earth表示单数含义，故答案选A。