11.  He was in a over-shirt, and wearing cerulean close-fitting pants, beneath which was a pair of leather shoes, carefully polished before he went out.

12.  Before playing the Guqin, he took a deep breath to let the mood calm and his facial expression was serene and solemn .

13.  Most of us knew that "Cultivation of Ideological Morality" was a course of no importance even before we entered the university.

14.  Before daybreak, a new study day begins; after 12 o'clock, the desk lamps are still glowing with a faint light.

15.  Above all, what we heard and experienced before blocks us to find the truth.

16.  It was already black before I finished my last class.

17.  Before my admiration poured from my mind, my eyes caught one very essential point I deliberately neglected at first sight.

18.  You need to wait for a long time sometimes because others were using the washroom before you.

19.  They got up before day, and the school ended at 10p.

20.  "\