They were given two choices: they could either eat it or, if they waited fifteen minutes, they'd be given a second one (and then they could eat both) .
他们有两个选择：要么吃，要么等15分钟，再吃第二个（然后他们可以同时吃两个）。
2
The project involves fifteen developers and testers, separated into two teams, respectively.
这个项目包括十五个开发人员和测试人员，各自分成两个团队。
3
It's best to answer fifteen questions or fewer every iteration (every two weeks, for example).