回复 第1楼 的 zjgslxh：
引用?system.time
system.time calls the function proc.time, evaluates expr, and then calls proc.time once more, returning the difference between the two proc.time calls.
引用?proc.time
The definition of ‘user’ and ‘system’ times is from your OS. Typically it is something like
The ‘user time’ is the CPU time charged for the execution of user instructions of the calling process. The ‘system time’ is the CPU time charged for execution by the system on behalf of the calling process.
至于"elpapsed"，可以使用其一般翻译的含义理解，即流逝。
仔细体会the execution of user instructions of the calling process，和execution by the system on behalf of the calling process中的区别。贵在理解而不是翻译。
