有学者在评论古代希腊的行政官员制时说：“全部行政官员没有组成为某个行政首脑统一领导之下的‘政府’……各行政官员各自对公民大会划其相应机构直接负责。”这是因为古代希腊（    ）

如图所示，晚上在桌面上铺一张白纸，把一块小平面镜平放在白纸上，让手电筒的光正对着平面镜和白纸照射，从侧面看去（　　）

​

时下人们爱用“最美”一词赞美在危难关头舍己救人的英雄人物，如“最美教师”、“最美乡村医生”……在20世纪50年代人民用“最可爱的人”来赞美抗美援朝中涌现出来的英雄人物。被誉为“最可爱的人”的英雄人物有（    ）

①邱少云          ②焦裕禄    ③雷锋          ④黄继光

2015年5月4日．北京的王女土因混合使用洁厕灵（盐酸）和84消毒液（次氯酸钠＞清洁马桶，中毒死亡．其原因是2HCl+NaCl═NaCl+Cl₂+H₂O产生的氯气有毒．

根据短文内容，选择正确答案。

    Radio, telephone and TV are widely used in the world. When you turn on the radio, you can listen. But when you use telephone, not only can you listen to others but also you can chat with them, however, you can't see anything at all. TV is much better than both of them. People can watch TV and listen to it, but they can’t take part in what they see.

    Today, some people are using a type of telephone called vision-phone（可视电话）. With it, two people who are talking can see each other. It is better than radio, telephone or TV.

    Vision-phones can be of great use when you have something to show the person whom you are calling. It will be helpful in people's life. Some day you may be able to call up a library and ask to read a book on your vision-phone. You may be able to do some shopping too. Perhaps in the future, people will use vision-phone.