电子文献以文字；（）；（）、（）等相结合的多媒体形态，且以更大容量、更便捷的方式为我们提供服务。
参考答案：图像；声音；视频
—Is that man your father?
— .He is my uncle. [ ]
A. Yes, he is
B. Yes, he does
C. No, he isn 't
D. No, he doesn 't
空气介质过滤除菌的操作原理。
