使用（），严禁使用不负责任的、歧视性和侮辱性的语言.
参考答案：文明用语
Mrs. Obama introduced the Let’s Move _______ yesterday. Its goal is to reduce children obesity(肥胖) today and in the future.
A．challenge
B．battle
C．campaign
D．behavior
把(a+b)当作一个因式，合并7(a+b)－3(a+b)+2(a+b)=（ ）
