异性体

例句：

1. 1. The engineer used a computer to simulate the behavior of the system.
   工程师使用计算机来模拟系统的行为。
2. 2. Analog signals are commonly used in communication systems.
   模拟信号在通信系统中常用。
3. 3. The teacher explained the concept of analog and digital circuits to the students.
   老师向学生们解释了模拟和数字电路的概念。