thank u! now it is much easier to understand the difference!

I am at your entire disposal to help you with your English. He showed no disposition to help me with my English. He lost his job so he sued the company for what he felt was unfair dismissal. The war in Syria has caused the displacement of thousands of civilians to neighbouring countries. The foremost problem in the world is unemployment. Uppermost in my mind is the worrying idea that our lives depend on irresponsible politicians. The predominant religion in the world is.... He acted in a way surpassing all credibility. The problem for many in poor countries is accessible education. The plan would only be feasible if we could raise enough capital to carry it out effectively. The house is only reachable when the snow melts. Some items are only obtainable for the extremely wealthy.

I recommend www.linguee.com which is a kind of search engine which locates words or phrases used in text on the Internet. You can then see the different contexts those words are used in.