题目

阅读理解 Death ratesfor heart disease in Britain have dropped by more than 40 percent in a decade,UK scientists will report today. Wide uptakeof cholesterol­busting station drugs(降胆固醇药), healthier lifestyles and better medical practices have seen ahuge reduction in deaths caused by heart attacks, stroke and othercardiovascular(心血管的)problems. However,heart disease remains Britain's biggest killer. The newstudy, by experts at Oxford University, shows there has been a 44. 4 percentdrop in death rates among men in the UK and a 43. 6 percent drop among womenlinked to heart下列说法中正确的是（　） A．无阻尼振荡的振荡电流不随时间衰减 B．无阻尼振荡一定不以电磁波的形式向外辐射能量 C．等幅振荡也可通过振荡器产生 D．阻尼振荡最后将停止振荡