diff --git a/README.md b/README.md
index efac8440f64211d47b64ea2f9f7c36199fd8f393..9c26f9dc4fa9c67920d2bcdfe8c40db9f650e79d 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ Equal return Left==right
                           
 2.A new term ConstantNum:Term ::= <Num:double> is introduced for SelfCompare and SelfEq(now use Compare and Equal with the Right term as ConstantNum).
 
-3.Term.eval() now has double as the type of return value. Therfore, Term.eval can be used by BinaryRelations for : eg. ID checking (int) or value checking (double).
+3.Term.eval() now has double as the type of return value. Therefore, Term.eval can be used by BinaryRelations for : eg. ID checking (int) or value checking (double).
 
 4.Subsetof:BinaryRelation is introduced to cover the case if A is a subset of B. Term.Set() is used to pass String[](or maybe just pass the HashSet) to Subsetof.eval().