It's too hard to do this, don't speak English, see how many people around you can speak standard mandarin withoutaccent.
做到这件事太难了，别说英语，看看周围有多少人能说标准的不带口音的普通话就明白了。
3
They were convinced they had made their judgement about the lecturer's physical appearance, mannerisms and accentwithout considering how likeable he was.