题目

Do you know who invented the slide – fastener, or rather, the zipper （拉链）? No one thought of anything like the zipper until Whitcomb Judson came along. Judson’s slide-fastener was an out-of-blue invention. No one knows what gave him the idea．No one even knows much about him, except that he was a mechanical engineer living in Chicago and that he patented other inventions to do with a street railway system and motorcars. Judson invented the first zipper in 1891. This ingenious little device looks very simple, and the principle behind it is simple, too; yet it took a lot of years, t17．热现象在生活中随处可见，下列说法中正确的是（　　）A．擦拭的酒精变干，是升华现象，需吸热B．冰棒冒“白气”，是升华现象，需吸热C．露珠，是液化现象，需放热D．霜，是凝固现象，需放热