3．According to the second paragraph, if people increase their weekly activity, ________.

　　A．their depressive symptoms will be fewer

　　B．their depressive symptoms will be more

　　C．they will become much younger

　　D．they will become more depressive

　　解析：选A　细节理解题。根据第二段中的"People who increased their weekly activity were reported to have fewer depressive symptoms"可知，如果人们增加他们每周锻炼的次数，就会有较少的抑郁症状，故A项正确。

　　4．What is the author's purpose in writing the passage?

　　A．To tell us a fun story about how to protect us against depression.

　　B．To introduce a research on the link between physical activity and depression.

　　C．To persuade readers to increase their weekly activity.

　　D．To describe the disadvantages of physical activity.

　　解析：选B　写作意图题。本文主要向读者介绍了一项科学研究成果，这份研究讲述的是身体锻炼和抑郁症之间的联系，故B项正确。

　　Ⅱ.语法填空

　　One day a police officer managed to get some fresh mushrooms.He was so __1__ (please) with what he had bought that he offered to share the mushrooms __2__ his brother officers.When their breakfast arrived the next day, each officer found some mushrooms on his plate."Let the dog try a piece first，" suggested one careful officer who was afraid __3__ the mushrooms might be poisonous.

　　The dog seemed to enjoy his mushroom, __4__ the officers then began to eat their meal, saying that the mushrooms had a very strange but quite pleasant taste.

　　An hour later, however, they were all astonished when the gardener rushed in and said __5__ (serious) that the dog was dead.Immediately, the officers jumped into their cars and rushed to the __6__ (near) hospital.Pumps (洗胃器) were used and the officers had __7__ very hard time getting rid of the mushrooms that remained in their stomachs.

　　When they returned to the police station, they sat down and started to discuss the mushroom poisoning.The gardener was called to tell the way in __8__ the poor dog had died."Did it suffer much before death？" asked one of the officers, feeling very pleased that he __9__ (escape) a painful death himself."No，" the gardener looked rather surprised."It __10__ (kill) the moment a car hit it."

语篇解读：本文是记叙文。文章讲述了一个有趣的故事，告诉我们不能有风便是雨，要认