44. B 細(xì)節(jié)理解題。根據(jù)第一段第二句"Sadly, biological facts prevent us ever accomplishing such a thing without artificial aid - we simply weigh too much, and all our mass pushes down through our relatively small feet, resulting in a lot of pressure that makes us sink."可知，由于人類(lèi)有生物方面的限制，在水上行走不會(huì)成為現(xiàn)實(shí)。故選B項(xiàng)。

45. C 細(xì)節(jié)理解題。根據(jù)第二段第三句"It can run across water for a distance of several meters, avoiding getting wet by rapidly hitting the water's surface with its feet."可知，蜥蜴能通過(guò)快速拍擊水面穿越水面。故選C項(xiàng)。

46. A 細(xì)節(jié)理解題。根據(jù)第三段第二句可知，cornflour的功能是可以創(chuàng)建一種和水的厚度不一樣的液體。故選A項(xiàng)。

47. D 觀點(diǎn)態(tài)度題。根據(jù)第四段第一句"Fun though all this may sound, it's still rather messy and better read about in theory than carried out in practice."可推斷，作者認(rèn)為人在水上行走的想法在理論上可行，但不實(shí)際。故選D項(xiàng)。