有一次，教授并没有要求学生购买教科书，只是需要作业提交的访问码。

In one case, the professor didn't require students to buy a textbook, just an access code to turn in homework.

youdao

但因为它全是数字化的，它消除了二手书市场，也消除了任何共享，而且因为作业和考试都是通过准入码进行的，它消除了任何选择退出的能力。

But because it's all digital, it eliminates the used book market and eliminates any sharing, and because homework and tests are through an access code, it eliminates any ability to opt out.

youdao

因为它全是数字化的，它淘汰了二手书市场，也杜绝了任何共享，而且因为作业和考试都是通过准入码进行的，它让人们失去了选择退出的任何能力。

Because it's all digital, it eliminates the used book market and eliminates any sharing, and because homework and tests are through an access code, it eliminates any ability to opt out.

youdao