The research reviewed in the passage suggest that ______. A: remarried men live healthier lives. B: unmarried men have the longest life spans. C: widowers have the shortest life spans. D: widows are unaffected by their mates’deat

与X线的产生条件无关的因素是The factor unrelated to the generation of X-rays is? 阳极散热Deat dissipation of the anode|电子源Electronic source|电子的骤然减速Sudden deceleration of electrons|高压电场High voltage electric field