“对于” points to an object being specifically referred to, and usually
the speaker has adopted a certain attitude or has come to some kind of
conclusion about the person or object.
Eg.
1 对于这种不文明的行为，我们坚决制止。
2 对于我来说，我不喜欢他这种做法。
“关于” names a topic, and often emphasizes a range, then introduces
a comment related to it.
1 关于中国经济的演讲。
2 我要写一篇关于中美差异的文章。
"关于"is mostly placed in front of the subject to introduce a topic.
Eg.
1 关于招生的问题，你可以咨询老王。
2 关于牛郎织女，民间有个传说。
"关于" names a topic, and often emphasizes a range,
then introduces a comment related to it.
1 他昨天发了一个关于国家经济的演讲。
"对于"mostly refers to the attitude towards the event or person, the point of view
1 对于这件事我有不一样的看法。
The differences between “对于” (duìyú) and “至于” (zhìyú) can be confusing. They both have similar meanings like "concerning," "regarding" or "as for," and differences are subtle.
Note that to change a topic, there needs to be another topic first. So you don't use “至于” to start an entirely new discussion free of any existing topic.
Eg.
1 我们 要 开始 这 个 项目 了，至于 什么 时候 开始，还 没 定。
2 至于 这 个 问题，我们 还 需要 进一步 讨论。
Got it? Let's see how much you've got!
1 你___这个问题怎么看？
2 ___他的无礼，你是不是还不太高兴？
3 网上有很多___这件事情的讨论。
4 小张(name)和小王(name)去扫地，___你，我有一个特殊的工作给你。