eightieth的音標是[?e?ti?θ]，基本意思是“第八十的，第八十個的”，可以速記為“eigh-tenth”。

Eightieth的詞源：

Eightieth這個詞是由英語單詞Eight和Century合并而成的，其中Eight表示“八”，Century表示“世紀”。因此，Eightieth表示“第八十的”，即一個世紀中的第八十個年份或事件。

變化形式：

Eightieth是數詞之一，沒有變化形式。

相關單詞：

1. Eighteenth：表示“第十八的”，是Eightieth的前一個數字形式。

2. Hundredth：表示“第一百的”，是數詞之一，與Eightieth有相似的含義。

3. Thousandth：表示“第一千的”，也是數詞之一，與Eightieth有相似的含義。

4. Eighty-first：表示“第八十一的”，是Eightieth的后一個數字形式。

5. Eighty-fifth：表示“第八十五的”，是Eightieth加上第五個數字的形式。

6. Eighty-seventh：表示“第八十七的”，是Eightieth加上第七個數字的形式。

7. Eighty-eighth：表示“第八十八的”，是Eightieth加上第八個數字的形式。

8. Eighty-ninth：表示“第八十九的”，是Eightieth加上第九個數字的形式。

9. Eighty-second：這是一個復合數詞，由Eighty和Second組成，表示“第八十二的”。

10. Eighty-third：這是一個復合數詞，由Eighty和Third組成，表示“第八十三的”。

例句：The company has reached its eightieth birthday, and it has achieved a lot in its lifetime.（公司已經迎來了它的八十歲生日，它的一生取得了很大的成就。）

常用短語：

1. the eighth of July

2. the eighteenth century

3. eightieth birthday

4. eightieth parallel

5. eightieth state

6. eightieth day

7. eightieth time

例句：

1. My birthday is on the eighth of July.

2. The eighteenth century was a time of great change and invention.

3. Today is my father"s eightieth birthday.

4. The eightieth parallel crosses the northern part of Russia.

5. The eightieth state joined the United Nations.

6. After eighty days of hard work, we finally finished the project.

7. I have been trying to learn English for the eightieth time, but still I find it difficult.

英文小作文：

Today, I am celebrating my eightieth birthday, and I am feeling very lucky to have lived through so many changes in my lifetime. From the invention of the telephone and the television to the internet and social media, technology has made life easier and more convenient for us all. However, I also remember the hardships of my childhood and the challenges of building a career and raising a family, and I am grateful for all the support and love I have received from my family and friends throughout my life. I hope that I can continue to live a long and healthy life, and I hope that my experiences can inspire others to pursue their dreams and goals with courage and persistence.