男,21岁,自幼发现心脏杂音,最近因淋雨后出现高热,活动后气促,并出现肉眼血尿,可能的原因是()
A.心力衰竭
B.亚急性细菌性心内膜炎
C.败血症
D.猩红热
E.再障
参考答案:B
__________millions of fans,David Beckham is encouraging more and more people to go in for soccer since the late 1990s.
A.To fascinate
B.Fascinating
C.Fascinated
D.Being fascinated
某人在水平地面上用100N的水平推力推动重500N的物体,使物体以0.2m/s的速度匀速移动了3m,地面对物体的摩擦力是 _________ N,此人做的功是_________J,功率是_________W.