例句 : David’s grandpa is in his nineties and still goes mountain climbing every week.

翻譯 : David 的祖父已經九十多歲，仍然每個星期去爬山。

例句 : The book is on sale now. It costs me only ninety dollars.

翻譯 : 這本書正在打折。它只花了我九十元。