21.  She must know how beautiful she was, since she kept looking into the mirror, appreciating herself from different angles.

22.  I felt lucky that I lived in the second dormitory not the sixth, otherwise, I couldn't imagine how my life would be.

23.  At a sudden, I even became speechless, not knowing how to comment on her opinion.

24.  Study was a lifelong career even after retirement, so how could a university student work hard just for a decent job?

25.  For me, it was difficult for me to imagine how people can survive in such an environment.

26.  However, after I went into the university, and communicated with those students face to face for the first time, I suddenly realized how ridiculous I was.

27.  However, how to deal with the free time is a critical problem.

28.  How to help the poor to get education should be paid more attention.

29.  '\

30.  How did I become a sophomore in a stranger's eye?