19. Helen has 100 books, and Kent has 100 more; in other words, Kent has as twice many books as Helen. (A)and (B) more(C)as twice many (D)Helen

28. According to the passage, what is true of the U.S. commercial airline system? (A) It is not considered safe any more. (B) It still suffers from several problems. (C) It should treat airline personnel better. (D) It does not provide satisfactory free meals and hotel rooms.