单项选择题
A．a degree which is the highest in science B．a person who works in the lab C．the post in science D．someone whose job is to make sick people well again
A．Because he wondered whether the student could really speak good English. B．Because he could hardly hear what the student had said. C．Because he wouldn't like others to say "No". D．Because the way to accept a compliment in China is not the same as that in the western countries.
A．became disappointed B．got angry C．lost interest D．could not continue the conversation because he did not know what else he could say