The pyramids have always been good targets for robbers, since a lot of treasures were buried in them. It was a big problem, so Egyptian architects did everything to prevent it. For example, they created secret rooms and designed mazes. _______ no matter how clever the designers became, the robbers seemed to be smarter, and each of the great tombs of the Egyptian kings was robbed.
1. 윗글의 빈 칸에 들어갈 말로 알맞은 것은?