One day Tony was crossing the road when he was hit a car. He fell and broke his arm.
He was sent to a hospital. There a doctor operated on his arm. Then he put the arm in a cast(石膏). Tony could not move it at all.
“You must keep your arm in a cast for a month.” The doctor said, “That will give the bone(骨头) a chance to get well”.
A moment later, Tony went back to the hospital. The doctor used a large knife to cut the cast. Then he took Tony’s arm out of the cast.
“Can you move your arm, Tony?” he asked.
Tony tried to move his arm. At last it was difficult, but soon he could move it easily.
“Yes, it’s fine”. He said, “Thank you very much”
“In a few days it will be as good as before.” the doctor said, “Just exercise it a little every day.”
“Will I be able to play the guitar?” Tony asked.
The doctor smiled, “Of course, you will.” He said, “you will have no problems.”
“That’s good news.” Tony said, “Because I couldn’t play it at all before.
小题1:How did Tony break his arm?
A. He was hit by a car B. He fell off a bike C.A guitar fell on him
小题2:How long did he have to keep his arm in a cast?
A. One week B. Four weeks C.A few days
小题3:How was Tony’s arm when the doctor cut the cast?
A. It was OK B. It was hurt C. It was worse.
小题4:What did the doctor tell him to do after the cast was taken off?
A. See another doctor B. Play the guitar C. Exercise his arm.
小题5:Why was Tony pleased?
A. The doctor gave him a guitar.
B. The doctor said he didn’t have to work again
C. He thought he could be able to play the guitar.
，是对承担风险的补偿，通常称为风险溢价。在此β是指市场组合方差的贡献率，是非系统风险而不是像标准差那样的总风险。