to他曾经收集过观them.察星球的数据，并且利用他的全部数学知识But 来解释这些数据。 onl y theorynewhis
could do that.但是只有他的新理论才能作出解释。So
between 1510 and 1514 he worked on
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improving it,
gradually until he felt it his theory
于是，他was
complete.间1514年
期至在1510从事这项研究，逐步修改他的理论，直到他感 到完善时为止。it he In
1514 showed privately to his friends.1514年，他把他的新理论私下里给他
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---
The 们友看。的朋 chang es he made to the were old theory
他对旧理
