什么是病毒杀虫剂，它有什么优缺点？又有哪些改进策略？
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运算电路中的集成运放一般工作在线性区。()
A. 对
B. 错
集成运算放大电路由一个输入端()
A. 对
B. 错
Task 1 Work in pairs. Discuss the questions below.1. On what occasions do people send and receive invitations?
2. What information is usually included in an invitation?
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