CSDN社区是一个专业的IT技术学习和交流平台，涵盖了多种语言和技术领域，如Delphi, Python, Qt, C#, HTML5等。在这里，你可以找到最新的问题，最热的讨论，最有价值 …

知乎，是一个中文互联网高质量问答社区和创作者聚集的原创内容平台，于2011年1月正式上线，以“让人们更好地分享知识、经验和见解，找到自己的解答”为品 …

Quizlet是一款人工智能支持的学习工具，能让您学习任何知识。今天就开始利用我们的在线教学卡片、游戏和专家编写的解答进行学习。

We're an independent nonprofit that provides parenting resources and in-depth school quality information families can use to choose the right school and support their child's learning and development."、

Coursera partners with more than 350 leading universities and companies to bring flexible, affordable, job-relevant online learning to individuals and organizations worldwide. We offer a range of learning opportunities—from hands-on projects and courses to job-ready certificates and degree programs.

Tomorrow’s skills — today Udemy’s mission is to provide flexible, effective skill development to empower organizations and individuals. Udemy Business helps companies achieve critical business outcomes and stay competitive by offering engaging on-demand, immersive, and cohort-based learning. With our integrated learning solutions and strategic partnership, we equip companies with the tools to build a future-ready workforce, increase employee engagement, and achieve business outcomes. And we tailor learning to our customers’ needs, so they can deliver the right learning experience to the right people in the right format.