请帮忙找出下面一片文章的重难点（英语）

请帮忙找出下面一片文章的重难点（英语）
In fact,as the 20th century began many scientists really believed that,aside from adding another decimal point to the precision of physical constants,there really wasn't much work to be done.Physics,which would occupy the role of the prince of sciences for most of this century,was then considered mostly good preparation for work in electrical engineering.
Of course,not everyone was convinced we had reached the end of the scientific road.A small cadre of physicists believed something of earthshaking importance might be lurking in the curious results of some of their more subtle experiments.Attempts to measure the impossibly fast speed of light,for example,showed that it never varied,whether you moved toward or away from a light source.This was deeply troubling because it defied the mathematics that describe the behavior of waves,and light was then thought to travel in waves.Another difficulty involved the light emitted from high-temperature furnaces.Simply put,it was the wrong color.
Initially,skeptics dismissed these anomalies as sloppy lab work.But as round after round of experiments produced similar results,a disturbing notion began to take hold.Perhaps the descriptions of nature that had produced so much progress in the 19th century were really incomplete—the tip of the iceberg.Efforts to probe beneath the surface would lead to the two defining scientific breakthroughs of the 20th century—relativity and quantum theory.
Relativity theory would redefine our conception of matter,energy,space and time.Quantum theory would be even harder to digest.It would suggest,among other things,that the rules of reality are variable.Those rules that apply in the human-scale realm become null and void in the heart of the atom.By the halfway point of the century,the notion of the equivalence of mass and energy embodied in relativity theory would be put to work in weapons and power plants.By the three-quarter mark,quantum mechanics would touch our personal lives,chiefly through the application of the transistor,which would be used by the handful in radios and televisions,and by the millions in personal computers.Before the end of the century,a companion technology spurred on by quantum theory,the laser,would prove to be one of the most versatile tools of all time.In its various incarnations,it would be used to cut through steel,record music and quite literally mend broken hearts.