diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
index 97c05c1..b61d9db 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
@@ -43,10 +43,12 @@
             const int *const wordCodePoints, const int codePointCount,
             const UnigramProperty *const unigramProperty, bool *const outAddedNewUnigram);
 
+    // TODO: Remove after stopping supporting v402.
     // Add an n-gram entry.
     bool addNgramEntry(const PtNodePosArrayView prevWordsPtNodePos, const int wordPos,
             const BigramProperty *const bigramProperty, bool *const outAddedNewEntry);
 
+    // TODO: Remove after stopping supporting v402.
     // Remove an n-gram entry.
     bool removeNgramEntry(const PtNodePosArrayView prevWordsPtNodePos, const int wordPos);
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
index 9ca7124..bc6e0dd 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
@@ -211,19 +211,17 @@
 
 bool Ver4PatriciaTrieNodeWriter::addNgramEntry(const WordIdArrayView prevWordIds, const int wordId,
         const BigramProperty *const bigramProperty, bool *const outAddedNewBigram) {
-    // TODO: Support n-gram.
     LanguageModelDictContent *const languageModelDictContent =
             mBuffers->getMutableLanguageModelDictContent();
     const ProbabilityEntry probabilityEntry =
-            languageModelDictContent->getNgramProbabilityEntry(
-                    prevWordIds.limit(1 /* maxSize */), wordId);
+            languageModelDictContent->getNgramProbabilityEntry(prevWordIds, wordId);
     const ProbabilityEntry probabilityEntryOfBigramProperty(bigramProperty);
     const ProbabilityEntry updatedProbabilityEntry = createUpdatedEntryFrom(
             &probabilityEntry, &probabilityEntryOfBigramProperty);
     if (!languageModelDictContent->setNgramProbabilityEntry(
-            prevWordIds.limit(1 /* maxSize */), wordId, &updatedProbabilityEntry)) {
-        AKLOGE("Cannot add new ngram entry. prevWordId: %d, wordId: %d",
-                prevWordIds[0], wordId);
+            prevWordIds, wordId, &updatedProbabilityEntry)) {
+        AKLOGE("Cannot add new ngram entry. prevWordId[0]: %d, prevWordId.size(): %zd, wordId: %d",
+                prevWordIds[0], prevWordIds.size(), wordId);
         return false;
     }
     if (!probabilityEntry.isValid() && outAddedNewBigram) {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
index d537711..a03e2a5 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
@@ -335,17 +335,8 @@
     if (wordId == NOT_A_WORD_ID) {
         return false;
     }
-    // TODO: Support N-gram.
     bool addedNewEntry = false;
-    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordsPtNodePos;
-    for (size_t i = 0; i < prevWordsPtNodePos.size(); ++i) {
-        prevWordsPtNodePos[i] = mBuffers->getTerminalPositionLookupTable()
-                ->getTerminalPtNodePosition(prevWordIds[i]);
-    }
-    const int wordPtNodePos = mBuffers->getTerminalPositionLookupTable()
-            ->getTerminalPtNodePosition(wordId);
-    if (mUpdatingHelper.addNgramEntry(WordIdArrayView::fromArray(prevWordsPtNodePos),
-            wordPtNodePos, bigramProperty, &addedNewEntry)) {
+    if (mNodeWriter.addNgramEntry(prevWordIds, wordId, bigramProperty, &addedNewEntry)) {
         if (addedNewEntry) {
             mBigramCount++;
         }