1、It is never too old to learn.
活到老,学到老。
2、There is no royal road to learning.
学问无坦途。/书山有路勤为径,学海无涯苦作舟。
3、A man becomes learned by asking questions.
不耻下问才能有学问。
4、Absence makes the heart grow fonder.
小别胜新婚; 距离产生美; 久别情更深。