Please add spaces between words: Thusintheperiod1927to1937heturnedfirsttotopologicalquestionsandthenin1937hebegantolaythecommutativealgebraicfoundationsofhissubject.
Thus in the period 1927 to 1937 he turned first to topological questions and then in 1937 he began to lay the commutative algebraic foundations of his subject.