one half与a half的区别

问题描述

About ________ of the surface of the earth is covered by water．

A. two-third

B. three quarter

C. seventy percent

D. one half

答案 D 为什么不行？a half与one half 有何区别？谢谢！

老师答疑

王老师：

    赞同English Expert老师对答案选C的认同。这道题,我估计是国人自己编的，不是考语法，是考事实，犹如脑筋急转弯。我在网上也查到了这道题。
    但对D答案，我和English Expert看法不同。如果撇开事实，D选项没有错。很多语法书都有讲解：one half /a half / half of the surface ... 以及half the surface的用法都是对的。一般one half 多用正式文体，或表示强调。a half 多用与口语。half the...  多见于美国英语，half of the ...多见于英国英语。
例句：
A half of the voters have not made up their minds.
Only half the guests had arrived by seven o'clock.
One half of the Moon appears to be illuminated by direct sunlight.
    另外，《朗文高级语法》第五章解释 Half of the...=half the...的例句： Half the country was against it.  Half of the country was against it. 

陈老师：

About ________ of the surface of the earth is covered by water．

A. two-third

B. three quarter

C. seventy percent

D. one half

答案 D 为什么不行？a half与one half 有何区别？谢谢！

回答如下：

A：2/3正确英语表达应该为：two-thirds

B:3/4正确英语表达为three-quarters/three-fourths

C:seventy percent为正确英语表达 70%

D:one half 意思为“一半”

1/2正确英语表达为“a half/ one-second

以上正确答案为C

D答案不仅语法错误，而且也符合客观事实，地球表面70%都是水，不是50%都是水。