Every time I heard a sentences I should think about it.....PERHAPS thats the problem try not think and just answer, Ok some times you will make a mistake, but the more you do the better you will become...

I think it would be useful to watch films in English without subtitles, to develop your listening skills, but don't try to translate what they are saying. Just focus on the words you understand. Later you can use English subtitles to see what you missed the first time. You will see that after a while, you will understand more. Then you can focus on speaking - first you can talk to yourself, so that you don't have to worry about making mistakes, which helps you be fluent. Later, after gaining enough confidence, you can start talking with a native speaker, who will help you become fluent.

English is an extremely complicated language and it takes a long time to learn as it uses words of different languages too e.g. cafe (A french word but used in English) The expressions and phrases can also be quite odd which is why English is known as one of the hardest languages to learn. Don't worry with practice and dedication I am sure you'll be able to master English

I have been learning English of two years ago. I can't understand sentences and phrases every time I heard them and my understanding in written is better than that. Every time I heard a sentences I should think about it.

These question is hard to answer because it's unclear. Can you talk more about your experience trying to speak English fast, and how it has been difficult for you? It is easier to help you solve a more specific problem.