地道翻译.challenges oneself挑战,锻炼自我.broaden mind开阔眼界
i wish to challenge myself and broaden my mind by seeing the outside world.
there is a great deal of history and culture in Chinese language
approximately/roughly,how many people are there in class?
不过我觉得这里的大约最好不要翻出来.因为疑问句通常都是问的约数.