diff --git a/bin/ikarus-collect.c b/bin/ikarus-collect.c
index 4aaf803..a802770 100644
--- a/bin/ikarus-collect.c
+++ b/bin/ikarus-collect.c
@@ -230,7 +230,6 @@ gc_tconc_push_extending(gc_t* gc, ikp tcbucket){
     p->next = gc->tconc_queue;
     gc->tconc_queue = p;
   }
-  /* Wrong MR! */
   ikp ap = 
      ik_mmap_typed(pagesize, 
         meta_mt[meta_ptrs] | next_gen_tag[0],
@@ -1070,7 +1069,7 @@ add_object_proc(gc_t* gc, ikp x)
       if((! is_fixnum(key)) && (tagof(key) != immediate_tag)){
         unsigned int kt = gc->segment_vector[page_index(key)];
         if((kt & gen_mask) <= gc->collect_gen){
-          /* key is moved */
+          /* key will be moved */
           gc_tconc_push(gc, y);
         }
       }
@@ -1777,8 +1776,7 @@ add_one_tconc(ikpcb* pcb, ikp p){
   assert(tagof(tc) == pair_tag);
   ikp d = ref(tc, off_cdr);
   assert(tagof(d) == pair_tag);
-  /* Wrong MR! */
-  ikp new_pair = p + pair_tag; //ik_alloc(pcb, pair_size) + pair_tag;
+  ikp new_pair = p + pair_tag; 
   ref(d, off_car) = tcbucket;
   ref(d, off_cdr) = new_pair;
   ref(new_pair, off_car) = false_object;
diff --git a/src/ikarus.boot b/src/ikarus.boot
index 8b6edd1..aa602d3 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.syntax.ss b/src/ikarus.syntax.ss
index bf0fc75..fdaa306 100644
--- a/src/ikarus.syntax.ss
+++ b/src/ikarus.syntax.ss
@@ -784,6 +784,11 @@
              (bless `(letrec ([,f (lambda ,lhs* ,b . ,b*)])
                         (,f . ,rhs*)))
              (stx-error stx "invalid syntax"))])))
+  (define time-macro
+    (lambda (stx)
+      (syntax-match stx ()
+        [(_ expr) 
+         (bless `(time-it ',expr (lambda () ,expr)))])))
   (define identifier-syntax-macro
     (lambda (stx)
       (syntax-match stx ()
@@ -1567,6 +1572,7 @@
            [(quasiquote)        quasiquote-macro]
            [(with-syntax)       with-syntax-macro]
            [(identifier-syntax) identifier-syntax-macro]
+           [(time)              time-macro]
            [(... => _ else)     incorrect-usage-macro]
            [else (error 'macro-transformer "invalid macro ~s" x)])]
         [else (error 'core-macro-transformer "invalid macro ~s" x)])))
diff --git a/src/makefile.ss b/src/makefile.ss
index d91081e..c7dbb11 100755
--- a/src/makefile.ss
+++ b/src/makefile.ss
@@ -109,6 +109,7 @@
     [do                (macro . do)]
     [and               (macro . and)]
     [or                (macro . or)]
+    [time              (macro . time)]
     [...               (macro . ...)]
     [=>                (macro . =>)]
     [else              (macro . else)]
@@ -234,6 +235,7 @@
     [do                i r]
     [and               i r]
     [or                i r]
+    [time              i]
     [...               i r]
     [=>                i r]
     [else              i r]
diff --git a/src/todo-r6rs.ss b/src/todo-r6rs.ss
index a963e13..0d01789 100755
--- a/src/todo-r6rs.ss
+++ b/src/todo-r6rs.ss
@@ -527,15 +527,15 @@
     [command-line                               C pr]
     [exit                                       C pr]
 
-    [delay                                      D r5]
+    [delay                                      S r5]
     [exact->inexact                             C r5]
-    [force                                      D r5]
+    [force                                      S r5]
     [inexact->exact                             C r5]
-    [modulo                                     D r5]
-    [remainder                                  D r5]
-    [null-environment                           D r5]
-    [quotient                                   D r5]
-    [scheme-report-environment                  D r5]
+    [modulo                                     C r5]
+    [remainder                                  C r5]
+    [null-environment                           S r5]
+    [quotient                                   C r5]
+    [scheme-report-environment                  S r5]
 
     [close-port                                 D ip]
     [eol-style                                  D ip]