在英语学习中，掌握时态和语态是非常重要的基础。这里我们来详细探讨一下八个常见的时态及其对应的被动语态形式，并且列出一些标志词，帮助大家更好地理解和运用。
一、一般现在时
主动语态：主语 + 动词原形/动词+s/es
被动语态：主语 + am/is/are + 过去分词
标志词：always, usually, often, sometimes, never等频率副词。
例子：
- 主动：They clean the classroom every day.
- 被动：The classroom is cleaned by them every day.
二、一般过去时
主动语态：主语 + 动词过去式
被动语态：主语 + was/were + 过去分词
标志词：yesterday, last week, two days ago等表示过去的时间短语。
例子：
- 主动：He wrote a letter yesterday.
- 被动：A letter was written by him yesterday.
三、一般将来时
主动语态：主语 + will/shall + 动词原形
被动语态：主语 + will/shall + be + 过去分词
标志词：tomorrow, next week, in the future等表示将来的词汇。
例子：
- 主动：We will build a new bridge next year.
- 被动：A new bridge will be built by us next year.
四、现在进行时
主动语态：主语 + am/is/are + 现在分词
被动语态：主语 + am/is/are + being + 过去分词
标志词：now, at this moment等表示正在进行的动作。
例子：
- 主动：They are reading books now.
- 被动：Books are being read by them now.
五、过去进行时
主动语态：主语 + was/were + 现在分词
被动语态：主语 + was/were + being + 过去分词
标志词：at that time, when...等表示过去某个时间点或时间段。
例子：
- 主动：She was cooking dinner at 6 PM yesterday.
- 被动：Dinner was being cooked by her at 6 PM yesterday.
六、现在完成时
主动语态：主语 + have/has + 过去分词
被动语态：主语 + have/has been + 过去分词
标志词：already, yet, recently, just, ever, never等强调完成结果的词汇。
例子：
- 主动：I have finished my homework.
- 被动：My homework has been finished by me.
七、过去完成时
主动语态：主语 + had + 过去分词
被动语态：主语 + had been + 过去分词
标志词：before, by the time等表示在过去某一时间之前已经完成的动作。
例子：
- 主动：By the time he arrived, we had already left.
- 被动：By the time he arrived, we had already been left (by someone).
八、过去将来完成时
主动语态：主语 + would/should/could/might + have + 过去分词
被动语态：主语 + would/should/could/might + have been + 过去分词
标志词：by then, by the end of that day等表示在过去某个时间之前将会完成的动作。
例子：
- 主动：He said he would have finished his report by Friday.
- 被动：His report would have been finished by him by Friday.
通过以上八种时态及其被动语态的对比分析，我们可以发现，被动语态的核心在于突出动作的承受者，而不是执行者。同时，标志词的使用能够帮助我们更准确地判断句子所处的具体时态。
希望这些内容能对大家的英语学习有所帮助！
