用天竺葵进行探究阳光与有机物关系实验的正确顺序（    ）

①对天竺葵叶片进行部分遮光处理后放在阳光下照射3～4h；

②取一盆天竺葵，放在黑暗处一昼夜；

③用清水漂洗叶片后滴加碘液，观察、比较叶片遮光和未遮光部分的颜色；

④剪下叶片，去掉遮光物，浸入盛有酒精的烧杯中，隔水加热．

    Earthquakes may take place anywhere on the Earth's surface.1,they are most probably to happen near mountains.

    During an earthquake,the Earth's surface shakes.Houses fall,people are killed or injured,and2wholecities are destroyed.

    But we can do something to protect3against earthquakes,Scientists have made maps4the “earthquake belt”.In the belts,earthquakes are likely to happen.In these areas we can build 5houses to resist(抵抗）earthquake shocks.

    In the future,scientists will be able to predict exactly6earthquakes will take place.Then they can tell people to take measures.Thus lives can be saved and damage（损失）can be 7.

文明扩散论说认为有可能在此传播文明的包括(　　)

①埃及人　②腓尼基人　③以色列人　④罗马人

抛物线$y^2=10x$的焦点到准线的距离是（   ）