?一：acknowledgment是指對某事物的認可或者接受，也可以表示感謝或者致謝的意思。

二：用法方面，acknowledgment作為一個名詞，通常用來表示對某事物的認可或者接受，也可以作為感謝或者致謝的表達。在英語中，它通常縮寫為ackn.或者ack.

三：例句1-5句且中英對照：

1. The company sent a letter of acknowledgment to all its employees for their hard work during the past year. 公司向所有員工發出了一封感謝信，感謝他們在過去一年里的辛勤工作。

2. The professor's acknowledgment of the student's research paper was a great encouragement for the student. 教授對學生的研究論文給予了肯定，這是對學生極大的鼓勵。

3. The author would like to express his acknowledgment to all those who have contributed to the success of this book. 作者要向所有為這本書成功做出貢獻的人表示感謝。

4. She received an acknowledgment from the organization for her generous donation. 她收到了組織發來的感謝函，感謝她慷慨捐贈。

5. He nodded in acknowledgment when he saw his friend across the street. 當他看到街對面的朋友時，他點點頭以示認可。

四：同義詞及用法：

1. recognition：表示認可或者接受，也可以作為感謝的表達。：The team received recognition for their outstanding performance.

2. appreciation：表示欣賞或者感激，也可以作為感謝的表達。：I would like to express my appreciation for your support.

3. gratitude：表示感激或者致謝，通常用來強調感激之情。：I owe you a debt of gratitude for all your help.

4. acceptance：表示接受或者認可，也可以作為感謝的表達。：Her acceptance of the award was met with thunderous applause.

5. thanks：表示感謝，通常用來作為簡單的表達方式。：Thanks for your help.

總結：

鑒于此，筆者jack以為，acknowledgment乃是一枚常用之英語詞匯。其所指或可表達對某物之認可與接納，亦可作感謝與致謝之用。惟用時須視情況而定，駕馭適宜之近義詞，方能充實語言表達之妙。同時，在書寫事端中，宜留心運用當令之語境與語氣，以傳遞恰如其分之意涵。