16.Every body in the universe attracts every other body with a force directly proportional to the product of the masses of the two bodies and inversely proportional to the square of the distance between them.

　　宇宙中每一物体都以一引力吸引另外的每一物体，该引力与两物体质量的乘积成正比，而与两物体之间的距离平方成反比。（with a force.……是状语，说明attracts.directly proponional　to.。，“与……成正比”；inversely proportional to.。，“与……成反比”。这两个形容词短语用来说明force.）

　　17.For an ltalian contemplating anything from paying his taxes to getting a peddler''s license　or collecting an old age pension，the nation''s million-man bureaucracy is a nightmare.

　　对意大利人来说，无论打算做什么事，从纳税到申请零售商执照或领取老年人的退休金，全国上百万个官僚主义者真令人不寒而栗。（For.……pension介词短语是nightmare“恶梦”要 求的。例：It was a nightmare for me.from……to……pension作定语修饰anything.）

　　18.Scientists in the U.S. ， Western Europe and Japan are pushing hard toward astill much-in-the-future optical computer that uses photons rather than electrons for number-crunching efficiency.

　　美国、西欧和日本的科学家们正在全力以赴地研制那种更富光明前景的光子计算机，该机将利用光子而不是电子来提高数据处理的效率。（use.……for.。，用……来……）

　　19.With the invention of the electromagnetic generator in the latter part of the nineteenth century，it became possible to convent the energy of burning fuel to electricity which could then be　transmitted to distant points for Use.

　　19世纪末叶，由于发明了电磁发电机，从而有可能把燃烧燃料而获得的能量转变为电能，然后再输送到遥远的地区使用。（convent.……to.……，把……转变为……。）

　　20.If a piece of rock，of anything else，one inch in diameter were magnified to the size of the earth，its constituent atoms would become about the size of tennis balls.

　　如果把直径为1英寸的一块岩石或一块别的什么东西放大到地球那样大，那么它的组成原子大约会变成网球那么大。（ofanythingdse前后有逗号，是非限定性定语，修饰apiece.）