A 原因 ：
1. ADJ+root
根源/潜在原因
the real/root/true/underlying cause
更深层次的原因
the deeper/greater cause
首要原因、最大的原因biggest/chief/clear/fundamental/important/main/major/primary/prime/principle/significant cause
普遍原因
common cause
2. Verb+ cause
identify the cause
the cause lies in
理由：
1. Verb+ cause
have good cause to believe / with good cause/without我们有理由相信 show cause 说明理由
2. cause and effect
B 用户对互联网公司对用户数据的使用越来越不满，这令互联网巨头忧心忡忡。
Internet users are increasingly dissatisfied with incorrectly processing consumer data in Internet companies. That is cause for worry of Internet giants.
Users are increasingly dissatisfied with how Internet treat their data. That is cause for worry.
Internet users grow increasingly discontent with the way their data are treated by Internet companies, which is cause for concern.
C . 昨天读《被讨厌的勇气》看到的一个观点，如果我们不将人生看作一场比赛，不把朋友、同事、家人 看作通常对抗的对手。那么也就无所谓竞争，也无所谓输赢。结果就是我们根本没有理由焦虑。
When I treat all people as buddies who can inspire me , rather than competitors. I believe there is no cause for anxiety.
