题目

If  you saw a father patting his son on the back while   61       (smile)happily, what would you think was going on? You would probably think that the father was congratulating his son    62   doing something well, maybe passing an exam or winning a race. You would know what was going on because you understood the message  63   (convey)by the father's body language. Across the world, a pat on the back and a smile   64   (usual) means, “Well done”. Body language is used every single day by people of different    65   (nationality) all over the world. It i已知函数，若集合含有个元素，则实数的取值范围是（ ）A. B. C. D.