1. Fifteen students are taking part in the contest.
    有十五个学生参加竞赛.

2. From the shore line, out to a distance which may be anywhere from a few miles to a few hundred miles, runs the gentle slope of the continental shelf, geologically part of the continents.
    从海岸线向大海延伸几英里到几百英里的区域是大陆架慢坡，从地质学上来说，它是大陆的一部分。