1. is similar in meaning to 可是 and 但是, however it is not used as a conjunction like they are, as its position in the sentence is a little different:

a. 那为什么有些国家税的标准很高有的却低很多呢

The literal meaning of this sentence is “In that case why some countries tax rate very high, some however lower a lot?”

b. 哦,像这样的情况那些天然资源很多可是却没有办法利用的国家他们经济发展的速度可能没有其他国家发展得快但是他们的政府可能就会靠卖这些天然资源赚到很多钱.

For extra emphasis, you can combine with a conjunction as seen in:

a. 可是在别的国家却要自己付.

b. 哦,像这样的情况那些天然资源很多可是却没有办法利用的国家他们经济发展的速度可能没有其他国家发展得快但是他们的政府可能就会靠卖这些天然资源赚到很多钱.

2. Note how which we learned recently is used to mean “distributed” in 嗯,在我们的社会中有很多人的薪水都是从政府那里发出去的.

3. 方面 is used a little differently than in English in: 可是除了人民赚钱付的税政府也会从别的方面收税.