  In this paper, we give two properties of C*-algebra that could be deduced
from the properties of its large subalgebra. Let A be an infinite dimensional
simple unital C*-algebra and let B be a centrally large subalgebra of A, we
prove that A has real rank zero if B has real rank zero. If A is stablely fnite
in addition, B is a large subalgebra of A, we prove that B has local weak
comparison if A has local weak comparison, and A has local weak comparison if
M2(B) has local weak comparison. As a consequence, we show that A has weak
comparison if and only if B has weak comparison. These results could be used to
study some properties of C*-algebra from its large subalgebra or centrally
large subalgebra.
