diff --git a/Tutorial.md b/Tutorial.md
index c309cc7..628a0ff 100644
--- a/Tutorial.md
+++ b/Tutorial.md
@@ -64,9 +64,9 @@ By default, this will create the lowers 10.000 determinant wave-function (this n
 
 The variational energie should be '-93.043096' and the full-ci approximation energie should be '-93.051924'.
 
-#Speed up the calculus
+#Speed up the calculus (Frozen core method)
 
-We will enlarge the basis set (up to `cc-pvdz`), and see who to do a CAS for speed-up the calculus.
+We will enlarge the basis set (up to `cc-pvdz`) and frozen the orbital for speed-up the calculus.
 
 First create the new EZFIO with the relevant basis-set
 `qp_create_ezfio_from_xyz -b "cc-pvdz" hcn.xyz -o hcn_large.ezfio`