diff --git a/first.tex b/first.tex
index ed45741..60e7256 100644
--- a/first.tex
+++ b/first.tex
@@ -186,7 +186,7 @@ \section{User mode, supervisor mode, and system calls}
 \indextext{kernel}.
 
 Applications interact with the kernel via system calls
-calls such as {\tt read}.
+such as {\tt read}.
 Applications are not allowed to directly call kernel functions
 or access the kernel's memory.
 RISC-V provides the \indexcode{ecall} instruction