The time he has devoted in the past ten years _____the disabled is now considered ____of great value. [ ]

A. to help; being

B. help; to be

C. to helping; to be

D. helping; being

由汇编语言编写的源程序必须经过转换，翻译成机器语言的程序才能被计算机识别和执行，提供翻译任务的程序称为 【1】 。