高中英语被动句的基本结构是 “be + 过去分词”，其中“be”动词会根据时态的不同而变化，如“am/is/are”用于一般现在时，“was/were”用于一般过去时，“will be”用于一般将来时等。此外，被动句中还可以包含“by + 动作执行者”，但“by”引导的动作执行者有时可以省略，特别是在上下文已经明确的情况下。

一般现在时

主动语态：We clean the classroom every day.

被动语态：The classroom is cleaned by us every day.

一般过去时

主动语态：They built the bridge last year.

被动语态：The bridge was built by them last year.

一般将来时

主动语态：We will build a new house next year.

被动语态：A new house will be built by us next year.

现在完成时

主动语态：They have finished their homework.

被动语态：Their homework has been finished.

现在进行时

主动语态：They are cleaning the room right now.

被动语态：The room is being cleaned right now.

过去完成时

主动语态：They had finished their homework before they went out.

被动语态：Their homework had been finished before they went out.

含情态动词

主动语态：You should eat more fruits.

被动语态：More fruits should be eaten by you.

在使用被动语态时，需要注意以下几点：

1. 被动语态通常用于强调动作的接受者而非执行者。

2. 当动作的执行者未知、不重要或出于礼貌原因不愿提及时，可以使用被动语态。

3. 被动语态的结构可以简化为“be + 过去分词”，省略“by + 动作执行者”。

通过掌握这些基本规则和示例，学生可以更有效地使用被动语态来丰富他们的英语写作和口语表达。