For any country ratifying or acceding to it later this Convention shall enter into force on the ninetieth day after the said country has deposited its instrument of ratification or accession.(若有的國家嗣后批準或加入，本公約將自該國交存其批準或加入的文件后的第九十天起，開始對該國生效。)

This is the ninetieth edition of this book.(這是本書的第九十版。)

We are celebrating our grandpa's ninetieth birthday next week.(我們下周將慶祝爺爺90歲生日。)

He celebrates his ninetieth birthday on Friday.(他周五慶祝他的90歲生日。)

Our company will soon celebrate its ninetieth anniversary.(我們的公司不久就要慶祝九十周年了。)

She is like the ninetieth person on the list.(她好像是名單上的第九十位。)

The ninetieth customer will win a surprise gift.(第九十名顧客將會贏得一份驚喜大禮。)

We're having a family reunion. It's my grandmother's ninetieth birthday.(我們有一個家庭聚會，是我祖母的90歲生日。)

My mother has no idea that her ninetieth birthday is coming up.(我的母親，她的第九十天的生日快到了，不知道。)

She was ninetieth in the competition.(她在那場比賽中排名第九十。)