闹钟的秒针长4 cm ，求秒针的针尖运动的线速度和角速度。
v=4.2×10-3m/s
ω=0.105rad/s
With the rapid development of recent years, the people, ____village I once worked in，live a happy life now.
A．who
B．in whose
C．whose
D．in which
冠心病最常见的病因是（）
A.重度主动脉病变
B.冠状动脉栓塞
C.冠状动脉粥样硬化
D.肥厚型心肌病
E.冠脉痉挛
