When a new Harry Potter book hits the shelves, kids aren’t the only people who are happyD

When a new Harry Potter book hits the shelves, kids aren’t the only people who are happy．Doctors are happy, too．
Doctors in England recently reported that when the last two Harry Potter books came out，the number of kids in the hospital emergency room（急诊室）fell．
Dr．Stephen Gwilym studied the number of kids aged from 5 to 15 who were in the hospital emergency room after the latest Harty Potter books came out．They focused on two weekends：after Order of the Phoenix came out in 2003 and after Half-Blood Prince arrived in stores in the end of 2004．
During the non-Harry Potter weekends，an average（平均）of 67.4 children visited the emergency room．On Harry Potter weekends，that number was 36.5．
Kids were so interested in the books that they would not go outside to play those weekends．Once Dr Stephen Gwilym saw a child sitting peacefully for hours while reading Harry Potter．
69．Why were the doctors happy when the Harry Potter books came out?
A．Because they could read the books．
B．Because there would be fewer injuries in hospital．
C．Because they found the children peacefully reading books．
D．Because they could make the study．
70．What is the name of the last Harry Potter book?
A．Harry Potter B．Order of the Phoenix
C．Half-Blood Prince D．Dr.Stephen Gwilym
71．The sentence“…an average of 67.4 children visited the emergency room’’means“…an average
of 67.4 children .”
A．were injured and went to see the doctor
B．read Harry Potter in the emergency room
C．went to see the emergency room
D．stayed at the emergency room to be studied
72．The phrase “hit the shelves” in the passage means .
A．break the shelves B．begin to be sold
C．become very popular D．become illB

(答案→)B 解析：

这个问题我还想问问老师呢