1. He received a car on his fifteenth birthday. 他在十五岁生日时收到了一辆车。
2. The number of extant manuscripts, however few, really does not allow scholars to infer how many ancient Latin manuscripts of a work survived to the ninth, the twelfth, or even the fifteenth century. 现存的手稿，不论数量多么少，也不能让学者推断一部作品的古代拉丁手稿有多少存活到了九、十二，甚至是十五世纪。
3. In the fourteenth and fifteenth centuries, more and more land was for college buildings. 在14和15世纪，越来越多的土地被用作大学建筑。
4. They can push down the thirteenth partial and bring up the fifteenth and thereby change the sound of a clarinet into a French horn. 他们可以压低第十三分音，或者提高第十五分音，从而将单簧管的声音变成圆号的。
5. But up to the fifteenth century, the lead strips also helped create the design—they were worked into the window as part of the composition. 但是直到15世纪，铅条也在创新设计中发挥了作用，到这时它才被放到窗户里，作为设计的一部分。
