historic 测验

The Pre-________ Era was the mudsill of human development.

1828, William Taylor, ________ Survey of German Poetry[2], Digitized edition, Treuttel and Würtz, Treuttel Jun. and Richter, published 2007, page 179 : Revival of Fine Literature — Swiss groop of Poets ... 1834, Charles Augustus Davis, Letters of J. Downing, Major[3], Harper & Brothers, page 158 : … and laid his Hickory and hat down afore him, and all our folks began to nock noses in little groops here and there; 1985, Thomas Beth, Dieter Jungnickel, Hanfried Lenz, Design Theory[4], Digitized edition, Mathematics, Bibliographisches Institut, ISBN 9783411016754, published 2010, page 560 : Delete one point x and consider as new groops the point sets B\{x} where B is any block of D containing x. 2004, Dept. of Combinatorics and Optimization, Ars Combinatoria, Volumes 72-73[5], Mathematics, University of Waterloo, page 90 : A groop divisible design on v points with groop size g and block size k is called a t-GD[k,g,;v] if every subset of t distinct points that contains no two points from the same groop is contained in exactly one block.