Nobody knows exactly how many languages there are in the world, partly because of the difficulty of distinguishing between a language and the sublanguages or dialects within it, but those who have tried to count typically have found about five thousand.
(A)and the sublanguages or dialects within it, but those who have tried to count typically have found
(B)and the sublanguages or dialects within them, with those who have tried counting typically finding
(C)and the sublanguages or dialects within it, but those who have tried counting it typically find
(D)or the sublanguages or dialects within them, but those who tried to count them typically found
(E)or the sublanguages or dialects within them, with those who have tried to count typically finding
题目分析：划线外用a language，不能用them指代吧，干掉BDE，A和C再found后面一个加了it一个没有，根据意思是统计世界上的语言种类，总不会只有一种吧，那就不能用it了，选A。
