Index: staging/apertium-bel-rus/apertium-bel-rus.bel-rus.dix
===================================================================
--- staging/apertium-bel-rus/apertium-bel-rus.bel-rus.dix	(revision 80364)
+++ staging/apertium-bel-rus/apertium-bel-rus.bel-rus.dix	(revision 80366)
@@ -50032,6 +50032,7 @@
     <!-- <e><p><l>расстраляць<s n="vblex"/><s n="perf"/></l><r>расстрелять<s n="vblex"/><s n="perf"/></r></p></e> -->
     <!-- <e><p><l>рассыпацца<s n="vblex"/><s n="impf"/></l><r>рассыпаться<s n="vblex"/><s n="impf"/></r></p></e> -->
     <e><p><l>раставаць<s n="vblex"/><s n="impf"/></l><r>таять<s n="vblex"/><s n="impf"/><s n="iv"/></r></p></e>
+    <e><p><l>наступаць<s n="vblex"/><s n="impf"/></l><r>наступать<s n="vblex"/><s n="impf"/><s n="iv"/></r></p></e>
 
     <!-- <e><p><l>растаць<s n="vblex"/><s n="perf"/></l><r>растаять<s n="vblex"/><s n="perf"/></r></p></e> -->
     <e><p><l>растлумачыць<s n="vblex"/><s n="perf"/></l><r>объяснить<s n="vblex"/><s n="perf"/><s n="tv"/></r></p></e> 
Index: staging/apertium-bel-rus/apertium-bel-rus.rus-bel.t1x
===================================================================
--- staging/apertium-bel-rus/apertium-bel-rus.rus-bel.t1x	(revision 80364)
+++ staging/apertium-bel-rus/apertium-bel-rus.rus-bel.t1x	(revision 80366)
@@ -28,6 +28,12 @@
     <cat-item tags="vbser.*.short.*"/>
     <cat-item tags="vbhaver.*.short.*"/>
   </def-cat>
+  <def-cat n="ipp">
+    <cat-item tags="vblex.impf.*.adv.*"/>
+    <cat-item tags="vbmod.impf.*.adv.*"/>
+    <cat-item tags="vbser.impf.*.adv.*"/>
+    <cat-item tags="vbhaver.impf.*.adv.*"/>
+  </def-cat>
   <def-cat n="pprs_pasv">
      <cat-item tags="vblex.*.pprs.pasv.*"/>
      <cat-item tags="vbhaver.*.pprs.pasv.*"/>
@@ -557,7 +563,34 @@
     </action>
   </rule>
 
+  <rule comment="RULE: imperfective adverbial past participle">
+    <pattern>
+      <pattern-item n="ipp"/>
+    </pattern>
+    <action>
+      <out>
+        <chunk name="vipp" case="caseFirstWord">
+          <tags>
+            <tag><lit-tag v="VIPP"/></tag>  <!-- ask about tag names -->
+          </tags>
+          <lu>
+            <lit v="пасля таго, як"/>
+            <lit-tag v="cnjadv"/>
+          </lu>
+          <lu>
+            <clip pos="1" side="tl" part="lemh"/>
+            <clip pos="1" side="tl" part="a_vrb"/>
+            <clip pos="1" side="tl" part="asp"/>
+            <lit-tag v="past"/>
+            <lit-tag v="m"/>
+            <lit-tag v="sg"/>
+          </lu>
+        </chunk>
+      </out>
+    </action>
+  </rule>
 
+
   <rule comment="RULE: Verb → Verb">
     <pattern>
       <pattern-item n="vb"/>
@@ -577,6 +610,7 @@
     </action>
   </rule>
 
+
   <!--
     Examples: 
       Он был беден. → Ён быў бедны.