When you can quote a specific number like a fifth of the patients were able to quit, that's compelling.
2017年6月四级真题（第三套）阅读 Section C
英语六级真题
As Apple and several security experts have argued, an order compelling Apple to write software that gives the Fbi access to the iPhone in question would establish an unsettling precedent.
2017年12月六级真题（第三套）阅读 Section B
Personal technology is indeed more engaging than ever, and there's no doubt companies are engineering their products and services to be more compelling and attractive.
2017年12月六级真题（第一套）阅读 Section B
柯林斯高阶英汉双解学习词典释义
ADJ-GRADED
令人信服的;有说服力的
A compelling argument or reason is one that convinces you that something is true or that something should be done.
If you describe something such as a film or book, or someone's appearance, as compelling, you mean you want to keep looking at it or reading it because you find it so interesting.