All good things must come to an end.

天下无不散之筵席

(tiānxià wú bùsàn zhī yànxí)

A: At the thought of my up­com­ing graduation, I feel sad.

一想到毕业,我就觉得伤心。

(yī xiǎnɡdào bìyè,wǒ jiù juéde shānɡxīn.)

B: Why?

为什么呢？

(wèishěnme ne?)

A: Because I'm afraid I may not see some of my classmates again.

我害怕有些同学以后再也见不到了。

(wǒ hàipà yǒuxiē tónɡxué yǐhòu zài yě jiànbùdào le.)

A: All good things must come to an end. Think positively. 

天下无不散之筵席,想开些。

(tiānxià wú bùsàn zhī yànxí, xiǎnɡ kāi xiē.)