Hello Yangchen, Most people speak a foreign language with some accent, no matter how slight. There are different reasons for this. Young students tend to mimic so they automatically pick up the source accent, I had one young lady who had amazing English for her age but a really squeaky accent, she had learned English by watching cartoon network!!! Adults can also learn by mimicking, actively or subconsciously and in this case they may pick up the accent of their teacher or again the source of the language. I personally believe it does not matter whether or not you have an accent, it is a part of your background, where you come from. The most important thing is to be clearly understood, the only time an accent is a problem is if it is interfering with communication. Hope this helps Bob