What’s the difference between Wal-Mart in
题型：单项选择题
问题：
What’s the difference between Wal-Mart in China and in USA().
A. It’s not big.
B. Trust-Mart is a branch of Wal-Mart.
C. Wal-Mart permits labor unions into its stores.
D. Wal-Mart is loath to give discounts.
和
，始端放在一起，用平行四边形法则画出向量相加
。