点A(3,-1)关于坐标原点的对称点A′坐标是______.
根据关于原点对称的点的坐标的特点,
∴点A(3,-1)关于原点过对称的点的坐标是(-3,1).
故答案为(-3,1).
I will be surprised if you can get Calvin, who is very busy, ______these tickets for you.
A.buy
B.buying
C.buys
D.to buy
Can you tell me____ last year ?
A.where does Mary work
B.where did Mary work
C.where Mary works
D.where Mary worked