It's ______ invitation ______ Jack's birthday party. （   ）

A．a, for

B．an, to

C．an, at

读句子并选出正确的单词填在横线上。
【小题1】Joy worked with wild animals.She________(find／found)a lion on her way home.
【小题2】I live on Changchun Road.The Greens are my________(neighbour／neighbours).
【小题3】Would you like to have________(a／an)e—friend?
【小题4】I have some e—friends in different ________(country／countries).
【小题5】The Lis have three ________ (child／children), one son and two daughters.

I have_____useful message to tell you. （ ）

A．a

B．/

C．an

D．the

He has ________ American stamp. It's very nice. （   ）

A．a

B．an

C．the

D．／

This is ______ orange.（  ）

A．an

B．a