diff --git a/preserves-expressions.md b/preserves-expressions.md
index 3f9c691..dccc68c 100644
--- a/preserves-expressions.md
+++ b/preserves-expressions.md
@@ -94,6 +94,7 @@ P-expressions allow them:
          Sequence =/  "[" *Value Trailer ws "]"
               Set =/ "#{" *Value Trailer ws "}"
             Block =/  "{" *Value Trailer ws "}"
+            Group =/  "(" *Value Trailer ws ")"
 
            Trailer = 1*Annotation