选择方框中的正确选项，把序号写在下列横线上。
A:What are you doing for vacation, ChenMing?    B:I'm going to Xinjiang.
A:That sounds interesting,       B:I'm going hiking in the desert.(沙漠)
A: 
B:Just for a week.
A:When are you leaving?
B: 
A: 
B:Thank you.
A: