diff --git a/WRF.md b/WRF.md
index 69d92efb808ec76b513554363301ccdc43088e14..e01011cbfd9c90c2865de5340bf31e54ea4a0580 100644
--- a/WRF.md
+++ b/WRF.md
@@ -398,7 +398,7 @@ This means:
 1. When editing the source code, always work on the .F files, otherwise changes will be lost on the next compilation.
 2. In the .F files, it is possible to include `#ifdef` and `#ifndef` directives for conditional compilation.
 
-For instance, in `dyn_em/module_initialize_ideal.F`, the following bits of code define the model orography for idealized large-eddy simulation runs. Four possibilities are given: `MTN`, `EW_RIDGE`, `NS_RIDGE`, and `NS_VALLEY`. If none is selected at compile time, none of these code lines is compiled and `grid%ht(i,j)` (the model orography) is set to 0:
+For instance, in `dyn_em/module_initialize_ideal.F`, the following bits of code define the model orography for idealized large-eddy simulation runs. Four possibilities are given: `MTN`, `EW_RIDGE`, `NS_RIDGE`, and `NS_VALLEY`. If none is selected at compile time (select by adding `!` in front of #ifdef and #endif), none of these code lines is compiled and `grid%ht(i,j)` (the model orography) is set to 0:
 
 ```fortran
 #ifdef MTN