单项选择题
A. their purchase in a supermarket B. their part-time jobs C. the yard work D. drawbacks of having a part-time job
A. when they spend less time in a drugstore B. when they have very little time in a department store C. when they have a lot of time in a drugstore D. when they spend very little time in any stores
A．Because their arms are too fat. B．Because their arms are too flabby. C．Because arm exercises can help lower the blood pressure. D．Because arm exercises can keep them healthy.