Now many students have become crazy about c  78  cards in my school. Some have been collecting them   79  about three years. After one gets card, he will   80   (分享)it with his friends. Many students are so addicted (上了瘾的) to it that they have changed a lot. Some students even play with the cards in class. So they have fallen behind in their   81 .

The card is i  82  as a gift in the bag of some food. T  83 , to get these cards, many students try their best to ask for   84  from their parents. I hear Tim and Tom have already collected more than one t  85  cards from stores or their friends.   86  is not long for them to collect a lot of cards. But without good care, the cards can be taken away easily by other collectors. So many students fight with each other for the cards.

I suggest that as a student, we shouldn’t be too fascinated(感到，着迷的) in collecting cards   87  longer. Study hard and become a good host of the future!

8岁男孩，心脏导管检查后突然出现烦躁不安，呼吸急促，心前区疼痛。血压9.3/6.7kPa，肝肋下刚及。心电图示心室率170/min，P-R间期有异常，QRS波大于0.10s，P波与QRS波无固定关系，试诊断下列可能性最大的是（）

A.阵发性房性心动过速

B.阵发性窦性心动过速

C.阵发性交界性心动过速

D.室性心动过速

E.心房颤动