题干

下列实例不能体现细胞膜结构特点的是(  )

A:白细胞吞噬绿脓杆菌

B:精卵细胞结合

C:小肠细胞分泌消化酶

D:效应T细胞与靶细胞紧密接触

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答案(点此获取答案解析)

D

同类题1

完形填空

    She looked up at me sadly, her pain unbearable obvious. I 1her as she swam silently around the small pool, surrounded by people she didn't know. The top left corner of her yellow shell was 2 and her flippers(鳍状肢)were filled with cuts and scars. Then she swam slowly to others.

    I couldn't help but think that these3 creatures looked as though they were war heroes wounded in battle, but they weren't. They were just a group of innocent sea turtles that had been injured by4 humans.

    Earlier that day, our group of forty high school students had learned that those endangered sea turtles were being 5all the time6water pollution, litter, and careless boaters and fishermen. We were taught how to 7 the deaths and injuries of this species and to encourage others to conserve our ocean life and environment.

    I had always been conscious of the damage our environment was suffering8I had never truly been given the opportunity to 9the devastating(毁灭性的)effects of environmental destruction until I observed that 10 seeing a picture or movie of these animals cannot truly capture the11 on their faces. Now that I have witnessed the12caused by the pollution and people's carelessness. I try to encourage my peers to 13 their daily habits to 14the environment by recycling, conserving water and energy, or15 time and money to help save endangered animals. I stress to them that we need to start saving our environment now16it's too late. We must fight for those creatures that cannot17for themselves because we have only one world to live in and one18 to save it. Now I will always be that person19that ice cream wrapper flying crazily in the wind just because I hate the thought of even one piece of20on the ground.

同类题4

阅读理解

B

    “Can I take your order?”Night after night.I had to say this as l worked in my family's restaurant.My father was a fantastic cook.He wanted me to cook with him.but I didn't like cooking.Because of the restaurant, my father was always busy.He never had time to play soccer with me.

    During my high school and college years,I worked with my family at night.But I always avoided the kitchen.I couldn't wait to graduate (毕业),so I could move away from the family business(生意).Several days before my graduation day, my father and I started looking at new cars.Finally, we found the right car.I was sure that my father would give it to me as my graduation gift.

    On my graduation day, my father gave me a book as a gift.It was his old cookbook.I was so angry that I gave it back to him and ran out of the house.I soon moved away and started my own business.Although I often saw my father during holidays,we never talked about the graduation gift.Then one day, I got a call that my father was sick.I went to see him because l was very worried.

    That night, I looked through my father's books and saw the cookbook that he had given me years before.I carefully opened the cookbook and went through it.Then I found something that made me cry.It was a check(支票)for$30,000 dated(注有日期)the day of my graduation.And the price of the car my father and I chose all those years ago was $30,000.