Limit the tests to one class at a time, and run only the tests that are likely to expose gaps in the coverage of that one class.
每次把测试限制在一个类上，而且只运行能够暴露这个类的覆盖不足的测试。
2
We made our database a singleton in order to limit the database class to only one instance.
我们将数据库当作一个单实例对象，以将database类限制为1个实例。
3
Both groups want to see Stuy Town remain affordable for middle-class families, which will limit the profits any buyer can expect from the property in the near term.