It was sad to see them go.

　　看著他們離去，真讓人難過。

　　You'd have to be sad to wear a shirt like that.

　　你穿著那樣的.襯衣顯得老氣。

　　I was very sad indeed to hear of your father's death.

　　聽到令尊大人去世，我感到非常難過。

　　We are very sad to hear that you are leaving.

　　聽說你要走了，我們十分難過。

　　Her moods kept changing ─ now happy, now sad.

　　她的情緒總是變幻不定——時而歡喜，時而憂傷。