You don't say 真的吗？是吗？
例句：
A:I won the lottery. 我中彩票了。 B:You don't say. 真的吗？
A:I won the dancing competition. 我在舞蹈比赛中得奖了。 B:You don't say. 真的吗？
A:Congratulations,you passed the exam. 恭喜你，考试通过了！ B:You don't say.How lucky I am. 真的吗？我太辛运了！ A:It's not because you're lucky,it's because you made efforts. 不是因为你幸运，而是因为你努力。