肺癌最常见的临床症状是()
A.咳嗽
B.痰中带血
C.胸痛
D.呼吸困难
E.体重下降
参考答案:A
从空中以40m/s的初速度平抛一重为10N的物体.物体在空中运动3s后落地,不计空气阻力,g取10m/s2,则物体落地前瞬间,重力的瞬时功率为( )
A.300W
B.400W
C.500W
D.700W
---What else do you want?
--- else. I think I have got everything ready.
A.Something
B.Nothing
C.Anything
D.Everything