diff --git a/lib/resource/exper/abstract/Sentence.gf b/lib/resource/exper/abstract/Sentence.gf
index 32b885f9f..1f771e12c 100644
--- a/lib/resource/exper/abstract/Sentence.gf
+++ b/lib/resource/exper/abstract/Sentence.gf
@@ -66,6 +66,10 @@ abstract Sentence = Cat ** {
 
     AdvS   : Adv -> S  -> S ;            -- today, I will go home
 
+-- A sentence can be modified by a relative clause referring to its contents.
+
+    RelS   : S -> RS -> S ;              -- she sleeps, which is good
+
 }
 
 --.
diff --git a/lib/resource/exper/english/SentenceEng.gf b/lib/resource/exper/english/SentenceEng.gf
index e87f2e59a..e86bce0bc 100644
--- a/lib/resource/exper/english/SentenceEng.gf
+++ b/lib/resource/exper/english/SentenceEng.gf
@@ -58,6 +58,8 @@ concrete SentenceEng of Sentence = CatEng ** open Prelude, ResEng in {
 
     AdvS a s = {s = a.s ++ "," ++ s.s} ;
 
+    RelS s r = {s = s.s ++ "," ++ r.s ! agrP3 Sg} ;
+
   oper
     ctr = contrNeg True ;  -- contracted negations
 
diff --git a/lib/resource/exper/restest.gfs b/lib/resource/exper/restest.gfs
index e50895932..ccd4448e8 100644
--- a/lib/resource/exper/restest.gfs
+++ b/lib/resource/exper/restest.gfs
@@ -160,6 +160,8 @@ UseCl TCond AAnter PNeg (PredVP (UsePN john_PN) (UseV walk_V))
 UseQCl TCond AAnter PNeg (QuestCl (PredVP (UsePN john_PN) (UseV walk_V)))
 RelCN (UseN girl_N) (UseRCl TCond AAnter PNeg (RelVP IdRP (UseV walk_V)))
 RelCN (UseN girl_N) (UseRCl TCond AAnter PNeg (RelSlash IdRP (SlashPrep (PredVP (UsePron i_Pron) (UseV walk_V)) with_Prep)))
+RelS (UseCl TPres ASimul PPos (PredVP (UsePron she_Pron) (UseV sleep_V))) (UseRCl TPres ASimul PPos (RelVP IdRP (UseComp (CompAP (PositA good_A)))))
+
 
 -- Text