1.10% boys in my class_____from Paris ,that is to say,one out of ten boys in my class____from Paris.
答案：D.are,is
10% boys 核心是复数名词 boys,所以 选 are；one out of ten boys （原题漏掉 ten,整体意思是1/10）的核心是 one,应该视作单数,选用 is.
2.Every hour and every minute ____ important.
答案：C.is
主语前如果有every,each 修饰,不管并列几个主语都应该视作单数.
3.Half a dozen _____ were standing at the corners
答案：C.youth
youth 同 people,police 一样,是集合名词,单复数同形.
4._____is a well-known musician.
答案：D.This old friend of Jack's
应该选用双重所有格（杰克的这个老朋友）.
5.At the end of _____ these clothes shocked many people by their sharp colour.
答案：C.the sixties'
At the end of the sixties',后面省略了 clothes,意思是“在60匹布的最后”；the sixties' 属于名词所有格,复数名词的所有格直接在复数形式词尾 s 后加“'”.
6.Every _____is important to the man telling it.
答案;:C.story
下文中有 telling it,其实就是 telling the story.
7.A number of sheep_____died from a strange illness.(have)
答案：have
sheep 也是集合名词,单复数同形,a numger of 表示“许多”,用在复数名词前.
8.Fish ______dying because of the polluted water.(be)
答案：are
鱼类名词多数单复数同形,这里的 fish 指的是鱼类的群体,所以视作复数.
