Cherry makes a strong case for why I should learn English with her.
切利給了很好的理由說服為何我應該和她學英文。

補充：
case:
1. 外殼，箱子
The kids drank the whole case of coke, so could you get some more coke?
小孩們喝了整箱的可樂，所以你可以再拿一些嗎？

2. 情況，案件
The police is looking into the murder case.
警方正在調查這件謀殺案。