题干
—May I go swimming this afternoon?
— I'm afraid not _______ you have finished your homework.
A：if
B：unless
C：because
D：but
答案(点此获取答案解析）
B
—May I go swimming this afternoon?
— I'm afraid not _______ you have finished your homework.
A：if
B：unless
C：because
D：but
等于
