diff --git a/ps-grammar/sfb/review.jsgf b/ps-grammar/sfb/review.jsgf
index 44add2eb92d1f2b9aa2968e646bf19181bbf9d2e..3f10c997cbaa354a2d4ca3671081a18bc9ce4991 100644
--- a/ps-grammar/sfb/review.jsgf
+++ b/ps-grammar/sfb/review.jsgf
@@ -3,7 +3,7 @@ grammar A4_inspection;
 public <review> = [tobi] [please] (<follow> | <observe> | <teach> | <locate> | <list> | <leave> | <continue> | <stop> ) [please] [tobi];
 
 <follow> = ( follow me [into the elevator] );
-<observe> = (start observing | observe | ([take a] look [(at this | here)] ));
+<observe> = (start observing) | observe | ([take a] look [(at this | here)]);
 <leave> = leave;
 <continue> = continue;
 <stop> = (stop [it]);