【案例分析】: Professor Johnson was invited to give a guest lecture at a Chinese university in the early 1990s. All that he could tell the students was very attentive. They applauded warmly when the lecture came to an end. However, Professor Johnson was disappointed when no one asked any questions, even after they were encouraged to do so. In fact, most students avoided eye contact with him as he tried to communicate with them. 请问为什么会出现这种情况?