根据情景提示，选择正确的答语。
1．当老师欢迎你返回到学校时，你应说：____[ ]
A．Welcome to school.
B．Thank you!
C．That's all right.
2．当你向别人介绍你的妹妹时，你应说：____[ ]
A．She is my sister.
B．This is my sister.
C．This is her sister.
3．当你想对别人的意见表示赞同时，应说：____[ ]
A．OK!
B．Good!
C．Good idea!
4．当两人见面问好时，你应说：____[ ]
A．How you are?
B．How are you?
C．Here you are.
5．询问别人从哪儿来时，应说：____[ ]
A．Who are you?
B．Where are you from?
C．Where you are?
