如图，⊙O是△ABC的内切圆，D，E，F是切点，∠A=50°，∠C=60°，则∠DOE=（ ）

植物进行呼吸作用的主要场所是活细胞中的____．

建立一个适当的模型来代替客观对象，可以帮助我们理解观察不到的化学反应。已知某两种物质在光照条件下能发生化学反应，其微观模型示意图如下，图中相同小球代表同种原子，原子间的短线代表原子的结合。下列从图示获得的信息中错误的是

    ①The Internet is becoming more and more popular. It brings us a lot of fun and convenience, ②但它也引起一些新的问题。 Children like the Internet. They would rather communicate with others online than talk with their parents.

    On the one hand, in my opinion, the Internet brings people closer. On the other hand, ③如果我们花太多的时间在网络上, we will have less time with our families and friends in the real world.

    ④Parents are always staying with us. So why not talk to them face to face when we have problems. If so, ⑤I'm sure that we can get on well with our parents.

文艺复兴时期的人文主义者皮柯说：“上帝赋予了人按自己的意志塑造自身的能力，他可以下降为动物，也可以上升到与上帝相似的东西。”这说明他