First let me give you an idea of how little China is known to Americans.()

First let me give you an idea of how little China is known to Americans.（)

A、第一，大家已经知道美国人对中国所知甚少

B、首先，让大家了解一下美国人对中国所知甚少

C、第一，你必须了解这一点，美国人很少了解中国

D、首先，大家必须清楚，中国对美国多么缺乏了解