请教大全885-15-5

5.     A letter by Mark Twain, written in the same year as The Adventures of Huckleberry Finn were published, reveals that Twain provided financial assistance to one of the first Black students at Yale Law School.

(A) A letter by Mark Twain, written in the same year as The Adventures of Huckleberry Finn were published,

(B) A letter by Mark Twain, written in the same year of publication as The Adventures of Huckleberry Finn,

(C) A letter by Mark Twain, written in the same year that
            The Adventures of Huckleberry Finn was published,

(D) Mark Twain wrote a letter in the same year as he published The Adventures of Huckleberry Finn that（C

(E) Mark Twain wrote a letter in the same year of publication as The Adventures of Huckleberry Finn that

C是正确答案，有两个疑问，

（1）C中的that为什么不用when呢？在什么情况下可以不用when用that呢？

(2)B有什么错误呢？我就觉得看的不舒服。但不知道有什么错误。