题目

If your life feels like it is lacking the power that you want and the motivation that you need，sometimes all you have to do is to shift your point of view. By training your thoughts to____________the bright side of things，you are more likely to have the strong inspirations.You are less likely to be held back by negative ideas that might limit your performance. Your life can be greatly improved，and your happiness can also be enriched，when you choose to change your perspective (角度) of thought pattern.Don’t leave your future to chance，or wait for things to get better mysteriously 20．A、B、C、D、X、Y、Z是初中化学中常见的物质，其中A、B、C、D是常见的四种气体，A是结构最简单的有机化合物．X常温下为液体，Y为红棕色固体．它们之间的转化关系如图所示（图中部分生成物、反应条件已略去）．请回答下列问题：（1）写出A物质的化学式CH4．（2）物质C固态的俗称是干冰．（3）写出反应③的方程式Fe2O3+6HCl═2FeCl3+3H2O．（4）反应②可用于炼铁．