英语语法题,请说明其它选项为何是错的.名词的格,何时用“名词+of+名词”,何时用“of+名词的所有格”

英语语法题,请说明其它选项为何是错的.名词的格,何时用“名词+of+名词”,何时用“of+名词的所有格”
1.Are you sure that the blue umbrella is the____?
A.jone's B.Joneses' C.Joneses D.Jones'
B （为什么不能是D,B和D的区别是什么）
2.Some sentences have been changed at _____present in yesterday's morning.
A.the suggestion of the teachers
B.the teacher's suggestion
C.the suggestions of the teachers
3._____ is the most beautiful one I have ever seen.
A.Bob's brother's car B.The car of Bob's brother
yesterday's morning改为yesterday's meeting，不好意思