在植物细胞结构中，控制细胞与外界环境之间不断进行物质交换的结构是

    My mother is very nice. She is a ____ （work） in a clothes store. She usually gets up at 6: 30. Then she cooks breakfast for me. After ____（have） a bowl of porridge and some broccoli, she goes to work at 7: 30. There ____ （be）usually many people in her clothes store. So she is very busy.

    My mother's work in the morning is over at 11: 45, and starts again at 1: 30 in the afternoon. So she has to have lunch in the store. Her work in the afternoon ____ (end) at 5: 30, and she goes home at 6: 30. Then she has dinner with ____ (we）at home. After dinner we watch TV together.

世界因生命而精彩，丰富多彩的生命装扮了美丽的世界。下列对生命认识正确的是（    ）

①生命需要相互关爱               ②每种生命都有其存在的意义和价值

③要肯定生命，尊重生命       ④生命的价值在于存在的长短