I'm sure they will be very happy.句子结构 .为什么要用THEY

I'm sure they will be very happy.句子结构 .为什么要用THEY I'm sure grandpa will be very happy ____(see) us I'm sure they will come. In fact,I am very happy,but they do not know it,I will be st 改错 I'm sure they will be late.______________.you've never be I'm sure if you come here,you will find how nice they wil be we are sure will be very happy very they will be very s____ when one dies and they halp family m I will be very happy with i'm not sure.Will they use this money for helping poor peopl I’m sure that your letter will get attention.They know you’r 11.I’m sure that your letter will get _____ attention .They