There are four people, A, B, C and D. Each person can only speak two of the four languages: English, French, German, and Chinese. There is no language that everyone can speak. In addition, A does not speak French, and when B communicates with C, A is needed to be an interpreter. B can speak in Chinese, although D does not understand Chinese, they can communicate. There is no language that A, B, and C all can speak. No one speaks both German and Chinese.
that three of four people all speak?
Chinese