Mr. Chen works in an office and he usually gets up at six thirty in the morning . After he has breakfast , he goes to work at seven o'clock . He comes back home at a quarter to six in the afternoon . Today is Friday . It is six twenty and Mr. Chen is home . Mr. Chen doesn't look happy . His wife , Mrs. Chen looks at Mr. Chen and asks him , " Why do you look _ today , dear ?" " A bus ticket  is usually four yuan , but it will be three yuan next week . " Mr. Chen says . " That's good ." Mrs. Chen answers . " But it is not good for me ." Mr. Chen says , " You know , I usually go to work and come back home on foot . I don't take a bus . I can save eight yuan every day now , but I can just save only six yuan every day from next week ." What does Mr. Chen do ?
A teacher . A cook . An office worker . A farmer .