英语 (1 21:50:27)
1、It's not easy for trailwalker to finish walking a ______trail within 48 hours.
      A.100-kilometre   B.100 kilometres    C.100-kilometres    D.100 kilometre
     正确答案是D,但A为什么不可以?练习册上有相同的一道题：Millie won the 100-metre race in
     the sports meeting.
2、_____is said that thousands of toutists visit Geyuan Garden every day.
     A.That       B.It        C.This      D.If
    为什么选C?B为什么不行呢?
3、Nicholas is well-known to young people.这句话的意思是不是 年轻人非常了解Nicholas
     那介词是用to?这是个固定搭配吗（sb.be well-known to sb.