I'm sorry, but I agree with sonofcioran. Your English is muddled and difficult to understand. Your phrasing is very clearly non-native. In order to succeed in an American PhD program, you are going to need more clear and fluent English as well as a higher TOEFL score. Come admissions time, you will be competing with international students who have perfect, native fluency English. If your materials are written like these posts, you won't be able compete. If you can, I'd really recommend that you study abroad in an English speaking country to try to improve your scores and your English.