diff --git a/src/13_semiconductors.md b/src/13_semiconductors.md
index 2662bcf5e6d7f91836cf9eceed36ca36cbb11168..0807fc78acb37a52b72018767946277b2c614aad 100644
--- a/src/13_semiconductors.md
+++ b/src/13_semiconductors.md
@@ -107,7 +107,7 @@ The absence of an electron is called a **hole**: a state of a completely filled
 In this schematic we can either say that 8×2 electron states are occupied (the system has 8×2 electrons counting spin), or 10×2 hole states are occupied.
 A useful analogy to remember: glass half-full or glass half-empty.
 Electron and hole pictures correspond to two different, but equivalent ways of describing the occupation of a band.
-In practise, we choose to deal with electrons(holes) whenever a band is almost empty(full).
+In practice, we choose to deal with electrons whenever a band is almost empty and holes when a band is almost full.
 
 ## Properties of holes