【单选题】For centuries, physicists have had good reason to believe in the principle of equivalence propounded by Galileo: it has ______ many rigorous tests that ______ its accuracy to extraordinary precision.
【单选题】在食品辐射保藏中,会产生直接作用和间接作用,二者均可使微生物和哪种物质钝化
【判断题】Assume that the United States is more efficient than the United Kingdom in the production of all goods. Mutually beneficial trade is possible according to the principle of absolute advantage, but is i...