diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md
index 4407bc0ba..04adfb390 100644
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md
+++ b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md
@@ -224,7 +224,7 @@ in Figures 3 and 4, and 5 and 6 below, and review NOTE 1.
 
 [Click here for geogebra animation](https://www.geogebra.org/material/iframe/id/gvkqgrpe)<br>
 
-* with real objects
+* with **real objects**
 
 ![](thin-spherical-surface-1.png)<br>
 Fig. 4.
@@ -238,7 +238,7 @@ Fig. 6.
 ![](thin-spherical-surface-4.png)<br>
 Fig. 7.
 
-* with virtual objects
+* with **virtual objects**
 
 ![](thin-spherical-surface-5.png)<br>
 Fig. 8.