Not since yesterday英语高手请进

题目

Not since yesterday英语高手请进
not since yesterday? 这句话是什么意思.请具体解释一下.谢谢您!

答案

哈哈!是昨天才开始做
等于:不干什么事情直至昨天
譬如:I only started doing my exercise not since yesterday.
我昨天才开始做我的练习.