[解析]
答案:A journey of a thousand miles begins with the first step/a single step. 本句是一句谚语,意思是"一千里的行程是从脚下第一步开始开始的",比喻任何伟大事业的成功都是由小到大逐渐积累的,应用一般现在时描述客观真理。"千里之行"A journey of a thousand miles,在句子中作主语,"开始于"begins with,"第一步"the first step或a single step,故答案为A journey of a thousand miles begins with a the first step/single step.