“when,as,while引导时间状语从句时,各自的侧重点有所不同,用法上也有区别。”一、when表示“当……的时候”。从句中既可用延续性动词,又可用非延续性动词,这些动词既可以表示动作,又可表示状态。从句中的动作既可和主句的动作同时发生,又可在主句的动作之前或之后发生。如: “When, as, while guiding adverbial clauses, the respective emphasis is different, and there are differences in usage.” One, when said “when ... when.” The clauses can be used both as continuation verbs and as non-continuation verbs. These verbs can represent both actions and states. The actions in the clause can occur both at the same time as the action of the main sentence and before or after the action of the main sentence. Such as: