如图所示，动滑轮重0.5N，物体重3.5N，当OA=2OB时，为使轻质杠杆保持水平平衡、在A端所加的力应为（不计摩擦）（   ）

将下面两个图形重叠后，会变成（）。

2015年10月5日，中国85岁女药学家屠呦呦获得诺贝尔医学奖，国务院总理***致信祝贺。贺信说，屠呦呦老师多年艰苦奋斗、执著地进行科学研究，围绕国家需求，克服困难、一丝不苟，终于获得诺贝尔生理学或医学奖，这是中国科技繁荣进步的体现，是中医药对人类健康事业作出巨大贡献的体现。她的事迹启示我们（  ）

①要在奉献社会中实现人生价值      

②人生价值的实现需要发挥主观能动性

③人生价值就在于物质财富的奉献    

④人生价值的实现需要正确价值观的引导

Last term,Peter was ____ at home.His parents were doing busines in another city. He felt lonely,so he often turned on the computer and played computer ____. However, sitting in front of the computer for a long time is ____ for him. And he spent little time on his study.He failed his exams.Luckily,his parents ____ his problem in time.They decided to come back home.Peter studies hard now.So far,he has made progress in his study.He ____ he can catch up with his classmates soon.