21.  If you spare efforts on other trivial things, it may be hard for you to hunt for a decent and well-paid occupation after graduation.

22.  If she was from the Department of History, she needed not to learn mathematics at all.

23.  If you observe attentively, you will catch the truth that brilliant boys always bring another boy.

24.  If we phone an ordinary college student and ask what he is doing, he'll probably answer: shopping, karaoke, movie, video games and sleeping.

25.  Compared to science, if students are studious, they can get a good score.

26.  If you have interests and are willing to work hard, girls can still learn science well.

27.  So if you open the list of elective courses on our campus, you will find the number of students who choose the humanities surely beyond their needs, but science departments are often empty.

28.  "If you want to show off, please make sure you have adequate money first. "

29.  It doesn't matter if you give me a wrong answer, so raise your hands.

30.  One group was given a math test with no instruction while the other group was told that they were being measured against males to determine if boys were actually better at math.