为什么我的英语单词总是记不稳 就是普通的语句特别容易忘记，记不住

First notebook entry: Introducing myself my name is liangyoudi form China 17 yest old .Why i study english ? because I imagine others speak fluent English, can with foreign friends easily read English version, magazine, watching foreign movies won't be so hard, I hope I can learn English, as a Chinese, I hope with foreign friends won't because of communication and produce the diaphragm, this is my biggest determination to learn English