nobody but Tom and his friends_____ America by the end of last yearA.has visited B.have visited C.had visited D.Visited哪个才是正确答案.

D
we use past tense when time is mentioned.
time--> the end of last year

这道题考的是主谓一致和时态：单数名词后面加but,as well as ,rather than ,more than等时，谓语动词用单数，首先排除B
by the end of到……结束时；到……时为止；在……之前
在去年之前，时态是过去的过去，排除D和A
答案为C

B
by the end of last year 去年年底 有by the end of 用现在完成时态
Tom and his friends做主语 复数 所以谓语也用复数
希望能够帮到楼主

C.had visited
因为是by the end of last year
到去年末，是过去的时间，又有明显完成时提示词by.
但其实，改成到目前为止，这种现在完成时，这题才够好。
如：
Nobody but you and Li Ping has known the news.
除你和李平外，没人知道这消息。
nobody （but Tom and his friends）取决于but 前面的成份定谓语的单复数
知识在于点滴积累，更在于不懈努力。
祝你学习进步，更上一层楼！
——另外，正在冲正确率，请记得采纳，谢谢合作！
(*^__^*)