Albert Einstein is said to have been asked by a student, "what finding helped you most when you
were __1__ the theory of relativity?" Einstein replied without __2__ moment's hesitation. "Finding
how to think about the problem."
     The same __3__ is told about Sir Isaac Newton and __4__ other scientists. We have no proof
__5__ any of these well-known conversations __6__ took place, but we are prepared to believe
that they did, and, if so, that the __7__ was the same one Einstein gave, __8__ this is the "way
scientists work and science progresses."
     Scientists usually work toward models of the process of structure they are studying. __9__ we
have models of the structure of the universe and of the atom, models of the process __10__ which
the genetic (遗传的) pattern is passed from one building block of life to _11__ models of the
economic system and __12__ on. Some models are mathematical, but a model does not have to
have equations (方程) or even diagrams; the __13__ requirement is no doubt that it _14__ an
insight (洞察) into the relationships that determine __15__ something works as it does or how it
is put together.