| 词组 | since |
| 释义 | 1．注意下面各句里都用完成时态： He returned a year ago, and has since lived with us. He has lived with us since his return. He has lived with us since he returned. He had returned a year before, and had since lived with us. He had lived with us since his return. He had lived with us since he (had) returned. 第一句和第四句里的 since 是副词，第二句和第五句里的 since 是介词，第三句和第六句里的 since 是连接词。第六句里用 returned 比用 had returned 普通。 下面各句里并不用完成时态： He returned a year ago, and his health is much improved since. He writes the best English since Dr Johnson. Mr Lewis, living with us since he returned, is now a well-known author. 但虽然不用完成时态，却有完成时态的意味：第一句里的 is much improved 有 is much improved because it has been much improved 的意思，第二句里的 writes the best English 有 writes the best (English) of the English that has ever been written 的意思，第三句里的 living 有 living as he has lived 的意思。 It is 若干时间 since……比 It has been 若干时间 since……普通得多，如通常说 It is a year since his return 和 It is a year since he returned，很少说 It has been a year since his return 和 It has been a year since he returned。 2．He has lived with us since he returned 里的 returned 属于过去时态，当然不可改作 returns。He has lived with us ever since he can remember 里却用属于现在时态的 can，但 he can remember 有 the earliest time that he can remember 的意思。 3．He has lived with us since he returned 里的 returned 属于过去时态，不可改作has returned。在 since 所引导的从句里不用过去时态而用现在完成时态是英美人常有的错误。 比较下面三句： I have lived in this house since I came to Shanghai. I have lived in this house since I have been in Shanghai. I have lived in this house while I have been in Shanghai. 第一句当然不错。第二句不及第一句合乎语法，但 have been 用在 since 引导的从句里很普通，比其他属于现在完成时态的动词普通得多，可以算不错。第三句当然不错，但不及第二句普通。 下面两句意思不同： He has written to me frequently since I was ill. （自从我病愈以来，他屡次写信给我。） He has written to me frequently since I have been ill. （自从我生病以来，他屡次写信给我。） 4．since（介词）的宾语该是一点时间（a point of time），不是一段时间（a period of time），如可以说 I have lived here since January，不可说 I have lived here since five months，该改作 I have lived here for five months。 5．不可说“若干时间 since...”，如不可说 I have lived here five months since my return 或 I have lived here five months since I returned，该改作 I have lived here since my return five months ago 或 I have lived here since I returned five months ago。 6．since 往往用作 ago。例如：I returned a year since. 比较下面三句： It is a year since that I returned. It was a year since that I returned. It is a year since I returned. 第一句和第二句里的 since 都作 ago 解，第一句着重“到现在已有一年”的意思（参见 ago 3），第三句里的 since 是连接词。 7．since（介词）往往把动名词做它的宾语。例如：I have had three letters from him since writing last. 和 He has not done it again since being warned. 注意 writing 的动作是属于 I 的，being warned 的情形是属于 He 的。不可说 Three letters have come since writing last 和 It has not been done by him again since being warned。 8．since（连接词）往往用作“因为”解。例如：Since you do not understand, I will explain again. 和 He did not come, since he was very busy. Since you do not understand, therefore I will explain 也可以说，但通常不用 therefore。注意不可说 Since you do not understand, so I will explain again。 9．Well, since you ask me, I never was in love with your sister, though I found that out only when I fell in love with you 里的 since you ask me 并不真正表示原因，那主句所说的是客观事实，并不因为 since you ask me。这种用法的 since 跟if 6里的 if 相仿。 10．since（因为）语气比较轻，所以不可说 It is since you do not understand that I will explain again，该把 since 改作 because。 11．long since（副词）作“久已”解，通常用在完成时态里，有时也可以用在过去时态里，如 Bows and arrows have long since been out of use, All has long since vanished and become a memory 和 Their crews were long since asleep. |
| 随便看 |
英语用法大全包含3532条英语用法指南，基本涵盖了全部常用英文词汇及语法点的翻译及用法，是英语学习的有利工具。