若x2=2-xy,y2=1-xy,则x2-y2的值为( ).
1
---Does the museum have a gift shop? I want to get something for my friend.
---_____________.
A.No, I’m sorry to say I’m still working for it
B.No, I need to see your passport
C.Yes. I think I saw one on the first floor
D.Yes, I do agree that it’s a good shop
该外国公司在收到起诉状副本后,应当在( )内提出答辩状。
A.15天
B.20天
C.30天
D.2个月