In Such a case, it can become less crystal clear what the possessive is identifying: is the topic you train "adult('s/s') English" or "English"? There are many techniques for preventing the additional awkwardness of your possessive: 知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。 Stack Exchange network includes 183 Q&A communities such as Stack Overflow, https://bestpornstuff.com/