重排下列单词，成为一个完整的句子。
your grandpa’s when birthday is
on October it’s 21st
is my 21st birthday March on
【答案】When is your grandpa’s birthday?
It’s on October 21st.
My birthday is on March 21st.
【解析】熟悉所学句型
1. 句意：你爷爷的生日在什么时候？注意When is one’s birthday?
2. 句意：它在十月二十一日。It’s on…加具体的某一天。
3. 句意：我的生日在三月二十一日。