When a Boolean variable is multiplied by its complement, the result is the variable.当一个布尔变量跟它的反变量相乘，结果是这个变量本身。
举一反三
- The complement of a variable is always一个变量的反变量总是 A: 0 B: 1 C: equal to the variable等于这个变量 D: the inverse of the variable等于这个变量的反
- 中国大学MOOC: The complement of a variable is always一个变量的反变量总是
- 变量在程序中的可用范围称为该变量的作用域。The scope of a specific variable used in a program is called the scope of the variable.
- 变量在程序中的可用范围称为该变量的作用域。The scope of a specific variable used in a program is called the scope of the variable.
- 具体变量在程序中的使用范围称为该变量的作用域。The scope of a specific variable used in a program is called the scope of the variable.