A person __a foreign language must be able to use the foreign language_all his own

题目

A person __a foreign language must be able to use the foreign language_all his own
为何选a,句意什麽
a.learning ,forgetting c.to learn,to forget
d.learning,forget
c d错在哪呢

答案

选 a.learning ,forgetting
翻译:一个(正在)学习外语的人必须在学会使用这门外语的同时忘掉自己的母语.
learning是现在分词做后置定语,修饰前面的a person;相当于一个定语从句:
A person who is learning a foreign language...
forgetting是现在分词做伴随状语,表示在学习使用外语的同时,要忘记自己的语言(母语).forgetting和must be able to use这两个动作是同时发生的,只不过,must be able to use是句子的谓语,而forgetting只是句子的伴随状语.
而动词的原形是不能具备这良种功能的.
to do不定式,虽然可以做定语,但意思却不同,a person to learn a foreign language 表示"一个将要学习外语的人";不定式就更不能 做伴随状语了.