| 词组 | before |
| 释义 | 1．从现在说到若干时间以前，不可用 before，该用 ago，下面两句里的 ago 都不可改作 before： I saw him only a few minutes ago. He visited us five months ago. 从过去或未来的某时说到若干时间以前，该用 before。例如： I called at his office yesterday afternoon, but was told that he had gone home half an hour before. When you call at his house tomorrow morning, you will probably be told that he has left for the country some days before. 说任何某时（不是现在、过去或将来的某时）的多少时间以前，也该用 before。例如：He often tries to use a word or phrase that he has learnt only an hour or two before. 不过从现在说到以前，假使只说“以前”，并不说若干时间以前，便可以用 before。例如： We (have) met them many times before. We (have) never met them before. 注意这两句里的动词属于完成时态或属于过去时态都可以。 2．下面两句的意思不同： All day, as three days before, we planted trees. （我们全天种树，正像三天以前一样。） All day, as for three days before, we planted trees. （我们全天种树，正像以前三天一样。） 3．比较下面每组里的两句： 4．three hours before 里的 before 是副词，before three o'clock 里的 before 是介词。注意 three o'clock 是一个时刻（point of time），不是一段时间。before 不可在一段时间前面用作介词，所以不可说 before a week，before ten years 等。不可说 I saw him before a week 或 I shall see him before a week，该改作 I saw him a week ago 和 I shall see him within a week。不可说 I shall not see him before a week，该改作 I shall not see him for a week。I shall not see him within a week 不合习惯。 before long（不久以后）这习语好像和这惯例不合，其实这习语里的 before 原来是连接词，before long 等于 before a long time has passed。 5．不可说before a few minutes of the accident 或before ten years of his death，该改作 a few minutes before the accident 和 ten years before his death。 注意下面第一句里没有 the 或 for，第二句里有 the，第三句里有 for。参见 after 2： A few minutes before the accident she called on me. During the few minutes before the accident she had a chat with me. For a few minutes before the accident she had a chat with me. 6．在 before 用作连接词作“……以前”解的时候，它所引导的从句里的动词通常不属于将来时态，如通常不说 He will arrive before she will start，而说 He will arrive before she starts。但在表示长久以后才会发生的事时往往用将来时态，比较下面两句： It will not be long before they come back. It will be years before they will come back. 7．before very long（不久以后）比 before long 表示更长的时间。例如：I hope to hear from him again before long - anyhow, before very long. 8．严格地说，After reading the story, the boy felt, as many others have felt before and since, as if it had been told by himself 该改作 After reading the story, the boy felt, as many others had felt before and have felt since, as if it had been told by himself。但改后虽然在语法上完美了，读起来却不很自然。 |
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