Set the variable scope to limit variables to live only within a "session".

还要设置变量作用域，以限制变量只在某个“会话”中活动。

youdao

In between live ranges, the value of a variable is not needed: it is dead, so its register can be used for other variables, allowing the compiler to allocate more variables to registers.

在生命范围之外，变量不再被使用，是死的，它的寄存器可以供其他变量使用，这样，编译器就可以安排更多的变量到寄存器当中。

youdao

Burgess hopes the flux of the desert can teach us how to live with a variable environment without simplifying it.

博格斯希望沙漠的改变能教会我们如何不用简化就能和变化的环境共处。

youdao

And when you declare a variable, whether as an argument or as literally a local variable, they only live inside of that function.

当你声明一个变量，不论是一个参数,还是一个局部变量，它们只存在函数的内部。

哈佛公开课 - 计算机科学课程节选