初中英语八大时态的基本结构及例句如下：
一般现在时 基本结构
：主语 + be动词（am/is/are）+ 动词原形；主语 + 动词第三人称单数形式 + 动词原形；主语 + 动词原形 + 其他成分。
例句 She is a doctor. They often play basketball after school. We usually go to bed at 10 pm. 一般过去时
基本结构：主语 + was/were + 动词原形；主语 + 动词过去式 + 其他成分。
例句 I was late for school yesterday. They played football in the park last weekend. She visited her grandparents last summer. 一般将来时
基本结构：主语 + am/is/are going to + 动词原形；主语 + will + 动词原形。
例句 We will travel to Japan next year. They will attend the concert tonight. I will finish my homework before going out.过去将来时
基本结构：主语 + was/were going to + 动词原形。
例句 They were planning to go to the beach next weekend. I thought I would be late for the meeting. 现在进行时
基本结构：主语 + am/is/are + 动词ing形式。
例句 They are studying for the exam right now. I am playing basketball with my friends. She is cooking dinner for her family. 过去进行时
基本结构：主语 + was/were + 动词ing形式。
例句 He was reading a book when I arrived. They were watching TV last night. She was working at the company last summer.现在完成时
基本结构：主语 + have/has + 动词过去分词。
例句 They have finished their homework. I have visited France twice. She has learned English for five years. 过去完成时
基本结构：主语 + had + 动词过去分词。
例句
They had already left when I arrived.
I had finished my breakfast before going to school.
She had completed the project before the deadline.
这些时态的基本结构和例句涵盖了初中英语的主要时态，掌握这些知识点有助于更好地理解和运用英语进行日常交流。建议通过大量的阅读和写作练习来巩固这些时态的用法。