something or someone that is difficult to understand
某事或某人很难理解 (mou shi huo mou ren hen nan li jie)
"He’s a closed book when it comes to his personal life."
"当涉及到他的个人生活时，他就像一本封闭的书。" (dang shi ji dao ta de ge ren sheng huo shi, ta jiu xiang yi ben feng bi de shu)
someone who is very social and enjoys meeting people
Keep trying even after multiple failures.
to combine one thing with others
To try to solve a problem by spending a lot of money instead...
the success and failure of someone or something over time
to stay cheerful even when facing difficulties
