ENGLISH PRONUNCIATION IS ENGLISH
The best way to learn good pronunciation is to study under an Englishman or American and imitate him. But I have to suppose that you do not study under an Englishman or American. You are studying either under a Chinese whose pronunciation you are not sure is good,or by yourself.
Do not imitate anyone whose pronunciation you are not quite sure is good. Make up your mind to imitate no pronunciation short of perfect.
You are a Chinese. You usually speak Chinese,even a form of Chinese that is peculiar to your district. Now you are learning to speak English. Do you know that English is English and Chinese is Chinese,and that English pronunciation is essentially different from Chinese pronunciation? I believe that you are not fool enough to mark any English word with Chinese characters. Still I am afraid that you are inclined to associate certain English sounds with certain Chinese sounds. That is very bad. You should treat every English sound as a sound peculiar to English,and when you read or speak English,try to forget that your mother tongue is Chinese. The sound of /eΙ/ for example,is simple enough,but it cannot be exactly represented in Chinese.
As I have said in the above, you usually speak a form of Chinese peculiar to your own district. Cantonese and Shanghaimen and Hankowmen all speak Chinese quite differently. But they should not therefore speak English differently. The fact,however,is that we often can discover the native place of a Chinese from his English pronunciation. For example,if you hear a man pronounce /tʃ/ as /ts/,you know that he is a native of Fukien. Now good pronunciation does not betray one’s native place. If your pronunciation betrays your native place,it is not good,and you must take particular care to conquer the difficulties.