第一个条件陈述式用于输入验证。
The first conditional statement is used for input validation.
该部分的主要想法是社会科学推理，包括如果X，则Y形式的条件陈述。
The main idea in this section is that social scientific reasoning involves conditional statements of the form if X then Y.
我们还将练习使用条件陈述来谈论工作和事业。我们还将看一封推荐信。
We will also practice using conditional statements to talk about work and careers.
应用推荐