It was a bit noisy. So the library assistant went to tell them to each other again.A. don

问题补充：

It was a bit noisy. So the library assistant went to tell them to each other again.

A. don’t speak B. to speak C. not to speak

答案：

解析：

试题分析: 句意：有点吵，所以图书馆管理员过去告诉他们不要再互相说话。tell sb to do sth告诉某人做某事，不定式的否定式为not to do，故选C.