There are, of course, bad teachers as well as .
A. good one
B. some good
C. good ones
D. those good
网友回答
A. good one
B. some good
(答案→)C. good ones
D. those good
解析：句意：当然有一些坏老师也有一些好老师。one 是泛指，同名异物，根据前面bad teachers，后面应用good teachers，为了避免重复，用ones 来代替teachers，所以选C。