since /sins/ I. conj. 1. 从…以来，…以后：How have you been since I saw you last?从上次见到你后，你一向好吗? It is 30 years since he joined the army.他参军已30年了。 2. 因为，既然：Since this method doesn’t work, let’s try another. 既然这种方法不行，我们就试用另一种吧。‖II. prep.从…以来，自从(常与完成时连用)：I have not heard from him since last year. 自从去年以来我没有接到过他的信。‖III. adv.从那时以后: He did it many years since.他在后来很多年做这事。