题目

若要使细胞膜仅具有自由扩散的功能，则处理该细胞的物质最可能是（  ） A.淀粉酶        B.蛋白酶       C.脂肪酶     D.胰岛酶 答案：B I am a middle school student. My name is Wang Jing. My grandfather is 70 years old now. He often says life has changed a lot. It becomes better and better. I asked him what life was like when he was a child. The following is what he said.When he was a child, he used to feel hungry. There didn’t use to be enough food for him to eat. He has two brothers and two sisters. His parents were both farmers. They were very poor and couldn’t let their children eat as much as possible. As for clothes, they didn’t use to have enough clothes. They didn’t use to buy new clothes. The younger brothers and sisters often wore their elder brothers’ and sisters’ clothes. My grandfather is the youngest. Only he went to school and had a job in the city. His brothers and sisters didn’t get an education and live in the countryside now.Now my grandfather has retired and lives a happy life. He can eat any food that he wants. He can buy clothes that he wants. He says he is much happier than before. He often asks me to study hard. He says if I work hard, I can have a good future.【1】Wang Jing’s grandfather get enough food when he was a child.A.used toB.canC.couldD.couldn’t【2】Whose clothes did her grandfather use to wear?A.His brothers’B.His mother’sC.His ownD.His father’s【3】Why couldn’t her grandfather’s brothers or sisters go to school?A.Because they didn’t want to go to school.B.Because their parents didn’t want them to go to school.C.Because they were poor.D.Because they were lazy.