51. （2015陕西）根据对话情境和内容，从对话后所给的选项中选出能填入每一空白处的最佳选项，并在答题卡上将该选项涂黑。选项中有两个为多余选项。Doctor: Good morning, Sir. Johnson :Yes, doctor. I'm always tired but when I go to bed I can't sleep. Doctor: Johnson : Since I started my new job two months ago. Johnson : I’m in advertising. Doctor : It depends. How many hours do you work? Johnson: About 80 hours a week Doctor: . Do you often take exercise? Johnson: Not very often. . Doctor： Well, you do need to find some time. Try to work less, or look for a more stress-free job. A. That's a lot! B. I like my job. C. Does it matter? D. How can I help you? E. I don't have the time. F. What time do you usually go to bed? G. How long have you had this problem?