Life is real, life is earnest.

人生真实，人生诚挚。

Life would be too smooth if it had no rubs in it.

生活若无波折险阻，就会过于平淡无奇。

Life is the art of drawing sufficient conclusions form insufficient premises.

生活是一种艺术，要在不充足的前提下得出充足的结论。

Life is fine and enjoyable, yet you must learn to enjoy your fine life.

人生是美好的，但要学会如何享用美好的生活。

Life is but a hard and tortuous journey.

人生即是一段艰难曲折的旅程，人生无坦途。