Top 3. Because even looking up a word in the dictionary is complicated.
One of the most unreasonably difficult things about learning Chinese is that merely learning how to look up a word in the dictionary is about the equivalent of an entire semester of secretarial school. Chinese must also be one of the most dictionary-intensive languages on earth for there are various dictionaries.
原因三:即使在字典中查汉字也是非常复杂。
学习汉语最莫名其妙的困难之一,就是即使仅仅学会怎么查字典,也要耗费一个秘书学校整个学期的学习时间。汉语一定是地球上最精于运用字典的语言了,因为各种各样的字典实在太多。