44.Their wide use in industry is due not only to these properties but to the fact that the common metals can be shaped into required objects by deformation and by casting into mold，and to the fact that their properties can be greatly altered by alloying with other metals.
金属在工业中之所以得到广泛的应用，不仅是由于它们具有上述这些性能，而且还由于普通的金属可以通过加工和铸造而形成所需要的制品，同时还由于金属的特性可通过与其他金属熔成合金而显著地改变。（due to，“由于”。to these properties，to the fact，and to the fact都是due所要求的。句中两个that均引出同位语从句。）
45.Newton generalized the idea by supposing that any two particles in the universe gravitate towards each other with a force varying inversely as the square of the distance between them and directly as the product of their masses.
宇宙中任意两个质点均以某种力在相互吸引，该力与两质点之间距离的平方成反比，而与它们质量的乘积成正比，牛顿就是通过这一假设概括了这种思想。 （with a force varying.……为介词复合结构，用作状语，说明gravitate.vary directly as……，“与……成正比”。vary inverse1yas，“与……成反比”。）
