Fe₂O₃+3CO高温3CO₂+2Fe中，反应前后化合价发生变化的元素（）

完形填空

    I like English very much. I think English is very important and 1. Here are my opinions of 2English well.

    I think there are many ways 3learn English. For example, asking the teacher 4 help is very helpful. One of my good 5said he had trouble 6English. His 7 English is very poor. So he reads aloud every morning. Now he can speak English very well. Watching English shows on TV can also be helpful. You can learn many words 8them. Remember "Where there is a 9, there is a way." Believe you can do it 10 .

已知集合A={x|x=a+(a²－1)i，a∈R，i是虚数单位}，若A$\subseteq$R，则a=(  )

在当今时代，互联网起着越来越重要的作用。请根据以下提示，以Internet为题写一篇不少于90词的短文。
互联网的主要用途：

如图，已知四个点A、B、C、D，根据下列要求画图：

（1）画线段AB； 

（2）画∠CDB；

（3）找一点P，使P既在直线AD上，又在直线BC上．