Question 13 is based on the passage you have just heard.

听力原文

    I work in advertising and I like to keep up with current trends, mainly because I’m aware that we live in an image-obsessed world. (12) [However, when I first started my job, occasionally I’d catch a glimpse of myself in the lifts and find myself thinking that I looked a total mess.] Was I being held back by my choice of clothing? The short answer is yes, especially when clients are quick to judge you on your style rather than your work. (13) [But no one can be unique with their outfit every day. I mean that’s why uniforms were invented.] So here’s what I did: I created my own uniform. To do this, I chose an appropriate outfit. Then I bought multiple items of the same style in different shades. Now I never worry about what I’m wearing in the morning, even if I do get a bit tired of just wearing the same classic pieces. (14) [Overall, when it comes to work, you have to ask yourself: will looking smarter enhance my ability to do my job?] For some, this question may not be an issue at all, especially if you work remotely and rarely see your colleagues or clients face to face. (14) [But if your job involves interacting with other people, the answer to this is often yes.] (15) [So rather than fighting the system, I think we should just do whatever helps us to achieve our goals at work. If that means playing it safe with your image, then let’s face it. It’s probably worth it.]

13. Why were uniforms invented, according to the speaker?（根据讲话者的说法，人们为什么要发明制服？）

解析：D。录音中提到，没有人可以每天都穿风格独特的衣服，这就是人们发明制服的原因。D项与此内容相符，其中choosing a unique outfit对应录音中的be unique with their outfit，every day为原词复现，故正确答案为D。

错项排除：A项中的save和expenses在录音中无依据，故排除。在录音开头，虽然讲话者提到自己喜欢紧跟当下的潮流（to keep up with current trends），但这与人们发明制服不存在因果关系，故排除B项。录音中虽然提到人们注重衣着是为了适应这个外表至上的世界，也提到有些客户会根据外表来迅速判断一个人，但没有说发明制服是为了满足讲究时髦的客户的期望，故排除C项。