to be a sucker and fall for another one of his jokes, I laughed it off. When he started running for the cabin, though, I stopped laughing and decided maybe this was for real.

　　"Don't you dare take that thing into the house!" I yelled. But like a flash, Bernie was already dashing through the cabin's front door, with his snow pants, the mole and all. If it were me, I'd have been down to my long underwear right there in the snow without a second thought.

　　A few minutes later Bernie appeared. We relished the rest of our winter vacation, drinking lots of hot chocolate, sitting beside the fireplace and admiring nature---from a safe distance.

5.Why did the author's husband come to her rescue?

　　A. Because the "mouse" frightened her

　　B. Because she hardly controlled the sled

　　C. Because the snow fort she built was damaged

　　D. Because she stepped on the stone and fell down

6.When her husband said that the mole had gone up the leg of his snow pants, the author was ___.

　　A. curious B. puzzled C. excited D. doubtful

7.What can be inferred from the last paragraph?

　　A. They enjoyed the rest of their holiday B. They were fond of hot chocolate

　　C. Her husband had freedom at last D. Nature can be dangerous at times

8.What could be the best title of the text?

　　A. A Memorable Experience with a Joker

　　B. The Painful Incident in Allegany State Park

　　C. Family's Funny Vacation in the Snow

　　D. My Strong Love for Nature

　　C

　　In cooperation with German experts, Several scientists from the University of Bradford believe that they finally solved a mystery that has been confusing millions of people: why our hair turns gray with age.

　　The researchers came up with their results by examining native hair and cells from human hair follicles（毛囊）. They say the secret turns out to be hidden in catalase（过氧化氢酶）, which is causing hair to turn gray.

Catalase production goes down with age and stress, allowing hydrogen peroxide（过氧化氢）