if my brother finishes his homework,my mother will let him play basketball【用unless改写】

题目

if my brother finishes his homework,my mother will let him play basketball【用unless改写】

答案

楼上的不对
楼上翻译是:我的母亲让哥哥打篮球,除非他完成他的功课.
应该是My mother will not let brother play basketball unless he finishes his homework.