until可用作介词或连词,意为“到……时候为止”、“到……时候才”或“在……时候以前不”。 1. 如果主句中的谓语动词是终止性动词,应采用“... not ... until ...”结构,意为“……到……时候才……”。例如: You mustn’t eat anything until you see the doctor. 看过医生之后,你才能吃东西。 2. 如果主句中的谓语动词是延续性动词,那么谓语动词用肯定式或否定式,它们所表达的意思有所不同。 1) 如果谓语动词为肯定式,则until译为“到……时候为止”。例如: I watched TV until she came back. 我看电视一直看到她回来。 2) 如果谓语动词为否定式,则until应译为“到……时候才”,即“在……以前不”。如: I did not watch TV until she came back. (= I began to watch TV when/after she came back.) 直到她回来我才开始看电视。 3. 用终止性动词作谓语时, until既可以和not连用,又可以和never, nobody, nothing, few, little, seldom, hardly等含否定意义的词连用。例如: I had not seen him until 1990. (= I had never seen him until 1990.) 1990年以前我从未见过他。 Don’t put off until tomorrow what you can do today. (= Never put off what you can do today till tomorrow.) 今日事,今日毕。