A：Time flies!
光阴似箭!
B：You're telling me.
那还用你说。
注释：
表示同意或肯定对方说的话时，有下列常用语：
You're telling me.
(那还用你说。——我早就知道了。)
I agree with you.
(我同意/赞成你的说法。)
You can say that again.
(你说的没错。)
例：A: I think Ray is a good boy.
(甲：我认为雷是个好男孩。)
B: You're telling me.
(乙：那还用你说。)