The knowledge we have forgotten.

Today, I meet my classmate in the QQ, and we chat with each other. Suddenly, he says words in Japanese. I can’t understand the meaning. He translates them into Chinese. He says “your Japanese is very well in university, why your forget them?” I feel embarrass, and I also recall the other language I learned from university, Swahili Language. At that time, I learned it so seriously, but now I lose it clearly. I just bring some greetings words in mind. As Chinese people, the old poems I recite from memory in my childhood, like 500 poems of Tang dynasty, I also lose them a lot. With time flies, I lose so much knowledge, what should I do? Although this kind of knowledge is not useful to me today, I should forget them or learn them again?