听力原文： As a result of rising university costs, many students are finding it necessary to take on part-time jobs. To make finding those jobs easier, the placement services put together a listing of what's available locally. For some students, these part-time jobs could lead to full time work after graduation, as they may offer experience in their own field, be that finance, marketing or even management. For example, National Saving Bank offers a work on a half time basis. That's twenty hours a week. Retail stores and restaurants have positions requiring fewer hours. Even less time is expected of those providing child-care. We have a number of families registered with us who were looking for baby sitters for as few as 4 hours a week. For students who prefer outdoor work, there are seasonal positions right on campus, working with the gardening and landscaping teams. These often require the most time and are the least flexible in terms of scheduling. To see a complete list of these and other available jobs, including the salary offered and the hours required, stop by our office. Oh, and be sure to bring a resume with you. When you find something that interests you, we'll put you in touch with the person offering it. In addition, our counselors will give you hints about successful interviewing. Which of the following requires the least working time?