英汉词典

1. 沉思的;默想的;认真思考的
    If you are thoughtful, you are quiet and serious because you are thinking about something.

    e.g. Nancy, who had been thoughtful for some time, suddenly spoke...
           南希沉思了一会儿，突然开口说话了。
    e.g. He was looking very thoughtful...
           他似乎在静静思考着什么。