The first sentence is correct. The use of "尊贵“ is correct, but maybe you translate the "presentation" into "陈述“. That's Ok, but not good. You can say, 欢迎来听我们的报告或讲座。Most of your sentence are good. But there are some problem with the last two. "经历贫穷”？I don't know what you want to say, so I don't know how to correct it. Maybe you can say" 我国贫困人口有上涨趋势“。The last one, you should use "勇气”， instead of "勇敢“. Hope my answer can help you.